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Metabolism Flashcards

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0
Q

What does kwashiorkor look like?

A

Child with a swollen belly

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1
Q

What is mneumonic for Kwashiorkor?

A

Malnutrition
Edema
Anemia
Liver change (fatty -from decreased synthesis of apolipoprotein)

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2
Q

What is marasmus?

A

Energy malnutrition resulting in tissue muscle wasting, loss of subcutaneous fat, edema

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3
Q

What is the difference between marasmus and kwashiorkor?

A

They have enough calories but lack protein in kwashiorkor.

They lack calories altogether in marasmus

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4
Q

What metabolism happens in the mitochondria?

A

Fatty acid oxidation
Acetyl-CoA production
TCA cycle
Oxidative phosphorylation

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5
Q

What metabolism happens in the cytosol?

A 
Glycolysis
Fatty acid synthesis
HMP shunt
Protein synthesis
Steroid synthesis
Cholesterol synthesis
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6
Q

What processes take place in both the mito and the cytosol?

A

HUG
Heme synthesis
Urea cycle
Gluconeogenesis

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7
Q

What is the rate determining enzyme of glycolysis?

A

Phosphofructokinase

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8
Q

What enzyme commits glucose to glycolysis?

A

Hexokinase/glucokinase

Adds and phosphate group using ATP

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9
Q

What is the rate determining enzyme in gluconeogenesis?

A

Fructose 1,6 - bisphosphatase

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10
Q

What is the rate determining enzyme of the TCA cycle?

A

Isocitrate dehydrogenase

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11
Q

What is the rate determining enzyme of glycogen synthesis?

A

Glycogen synthase

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12
Q

What is the rate determining enzyme of glycogenolysis?

A

Glycogen phosphorylase

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13
Q

What is the rate determining enzyme of HMP shunt?

A

G6PD

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14
Q

What is the rate determining enzyme of de novo pyrimidine synthesis?

A

Carbamoyl phosphate synthetase II

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15
Q

What is the rate determining enzyme of de novo purine synthesis

A

Glutamine-PRPP amidotransferase

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16
Q

What is the rate determining enzyme of the urea cycle?

A

Carbamoyl phosphate synthetase I

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17
Q

What is the rate determining enzyme of fatty acid synthesis?

A

Acetyl CoA carboxylase

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18
Q

What is the rate determining enzyme of fatty acid oxidation?

A

Carnitine acyltransferase I

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19
Q

What is the rate determining enzyme of kerogenesis?

A

HMG-CoA synthase

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20
Q

What is the rate determining enzyme of cholesterol synthesis?

A

HMG-CoA reductase

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21
Q

How many molecules of ATP are made by aerobic metabolism of glucose?

A

32 via malate-aspartate shuttle

30 via glycerol-3-phosphate shuttle

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22
Q

How many molecules of ATP are made by anaerobic glycolysis?

A

2 ATP per glucose molecule

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23
Q

What type of reactions is NAD used in?

A

Catabolic process

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24
What kind of reactions is NADPH used in?
Anabolic processes such as steroid and fatty acid synthesis Also: respiratory burst P-450 Glutathione reductase
25
What is the difference between hexokinase and glucokinase?
Hexokinase is ubiquitous with high affinity and low capacity. It is not induced by insulin Glucokinase is seen in only the liver and beta cells of the pancreas. It has low affinity and high capacity. It can be induced by insulin.
26
What inhibits hexokinase?
Glucose-6-phosphate
27
What inhibits glucokinase?
Fructose-6-phosphate ATP Citrate
28
What stimulates phosphofructokinase-1?
AMP | Fructose 2,6 bisphospate
29
What inhibits phosphofructokinase 1?
ATP | Citrate
30
Which steps in glycolysis require ATP?
The commitment step (glucose --> glucose-6-phosphate by glucokinase/hexokinase) The rate limiting step (G6P --> fructose 6 phosphate by phosphofructokinase)
31
Which steps in glycolysis make ATP?
Steps 7 and 10 1,3 bisphosphoglycerate to 3-phosphoglycerate. By phosphoglycerate kinase Phosphoenol pyruvate to pyruvate via pyruvate kinase
32
Which 2 enzymes are involved in the production of ATP in glycolysis?
Phosphoglycerate kinase | Pyruvate kinase
33
What stimulates phosphoglycerate kinase and pyruvate kinase?
Fructose 1,6 bisphosphate
34
Which enzymes regulate fructose 2,6 bisphosphate?
Fructose bisphosphatase 2 | Phosphofructokinase 2
35
Which enzyme is active during the fed state?
Phosphofructokinase 2
36
What does PFK-2 do?
Activates PFK-1 to convert F6P to F1,6BP
37
What does fructose bisphosphatase 2 do?
Activates fructose 1,6 bisphosphatase to convert fructose 6 phosphate to glucose 6 phosphate
38
What are the levels of glucagon, insulin, cAMP, protein kinase A and the PFK-2 and FBPase-2 during the fed state?
``` High insulin Low glucagon Low cAMP Low protein kinase A Low FbPase2 High PFK2 Net result = increased glycolysis ```
39
What are the levels of glucagon, insulin, cAMP, protein kinase A and the PFK-2 and FBPase-2 during the fasting state?
``` Low insulin High glucagon High cAMP High protein kinase A Low PFK2 High FBPase-2 Net result: decreased glycolysis ```
40
What are the signs of arsenic poisoning?
Vomiting Rice water stool Garlic breath
41
What does arsenic inhibit?
Lipoid acid
42
What is the product pyruvate dehydrogenase complex reaction?
Pyruvate + NAD + CoA --> acetyl-CoA + NADH + CO2
43
What cofactors are involved in the pyruvate dehydrogenase complex?
``` Pyrophosphate - B1 FAD - B2 NAD - B3 CoA - B5 Lipoid acid ```
44
What is PDC deficiency caused by?
X-linked mutation in gene for E1-alpha subunit
45
What does PDC deficiency result in?
Backup of substrate: pyruvate and alanine
46
What are the findings of PDC deficiency?
Neuro deficits starting in infancy
47
What is the treatment for PDC deficiency?
Increase intake of ketone is nutrients : fat and lysine/leucine
48
What is the function of PDC?
To transition from glycolysis to the TCA
49
What are the 4 products pyruvate can be converted to?
Alanine Acetyl-CoA Oxaloacetate Lactate
50
What enzyme converts pyruvate to alanine?
Alanine amidotransferase with the help of B6
51
What enzyme converts pyruvate to lactate?
Lactate dehydrogenase
52
What is lactate used in?
Anaerobic glycolysis and the cori cycle
53
What enzyme converts pyruvate to oxaloacetate?
Pyruvate carboxylase (b7) with CO2 and ATP
54
What can oxaloacetate be used in?
TCA or gluconeogenesis
55
What enzyme converts pyruvate to acetyl-CoA?
Pyruvate dehydrogenase with B1,2,3,5
56
Which organs use anaerobic glycolysis?
RBCs, WBCs, kidney medulla, lens, cornea, testes
57
What are the products of the TCA cycle?
3 NADH, 1FADH2, 2 CO2, 1 GTP per acetyl CoA = 10 ATP | And we get 2 acetyl CoA molecules per 1 glucose so multiply everything by 2
58
What is the starting and end product of the TCA cycle?
Citrate Is Krebs' Starting Substrate For Making Oxaloacetate: Citrate --> Isocitrate --> alpha-Ketoglutarate --> Succinyl-CoA --> Succinate--> Fumarate--> Malate --> oxaloacetate
59
What are the irreversible reactions in the TCA cycle?
Acetyl CoA --> citrate by citrate synthase Isocitrate to alpha Ketoglutarate by Isocitrate dehydrogenase (rate limiting step, produces NADH2) Alpha Ketoglutarate to succinyl CoA by alphaketoglutarate dehydrogenase (makes NADH2)
60
Which steps produce NADH2?
Isocitrate to alpha-Ketoglutarate Alpha-Ketoglutarate to Succinyl CoA Malate to oxaloacetate
61
Which step produces FADH2?
Succinate to Fumarate
62
Which step uses substrate level phosphorylation to generate GTP?
Succinyl CoA to Succinate
63
What is complex I?
NADH dehydrogenase
64
What is an inhibitor of complex I?
Rotenone | Amytal
65
What is the consequence of electron transport inhibitors?
They decrease the proton gradient and block ATP synthesis
66
What is complex II?
Succinate dehydrogenase
67
What is complex III?
Cytochrome b-c
68
What is an inhibitor of complex III?
Antimycin A
69
What is complex IV?
Cytochrome c oxidase
70
What inhibits complex IV?
Cyanide
71
What is complex V?
ATP synthase = f0/f1 F0= integral membrane protein with delta stalk attached to F1 F1= made of alpha/beta subunits - converts ADP to ATP
72
What inhibits complex V?
Oligomycin
73
What do complex 3 and 4 do
Pump hydrogen ions from the matrix to the inter membrane space creating a negative charge inside the matrix and thus a larger proton gradient
74
What is oligomycin?
It is an ATP synthase inhibitor
75
What is the MOA of oligomycin?
Increases the proton gradient and stops ATP synthesis
76
Which complex uses CoQ?
Complex III
77
What is the effect of 2,4 dinitrophenol, aspirin, and thermogenin on the ETC?
Uncouple the ETC --> increase membrane permeability causing a decrease in the proton gradient stopping ATP, but continuing electron transport --> produces heat!
78
What are the irreversible enzymes in gluconeogenesis?
Pathway Produces Fresh Glucose: Pyruvate carboxylase = pyruvate to oxaloacetate Phosphoenol carboxykinase = oxaloacetate to PEP Fructose 1,6 bisphosphatase = F1,6BP to F6P Glucose-6-phosphatase = G6P to glucose
79
What does the G6Pase reaction need in gluconeogenesis?
GTP
80
What does the pyruvate carboxylase reaction in gluconeogenesis need?
Acetyl-CoA, biotin, ATP
81
What is the function of the HMP shunt pathway?
To provide a source of NADPH from glucose 6 phosphate | Provide ribose for nucleotide synthesis and glycolysis intermediates
82
Where does the HMP shunt occur?
In the cytoplasm
83
Does the HMP shunt require ATP?
No
84
At what sites does the HMP shunt occur?
Lactating mammary glands Liver Adrenal cortex RBCs
85
What is the irreversible phase of the HMP shunt?
Oxidative | G6p --> 2 NADPH, CO2, ribulose-5-p by G6PD (rate limiting)
86
What is the reversible phase of the HMP shunt?
Nonoxidative | Ribulose-5-P --> ribose-5-p, G3P, F6P by phophopentose isomerase with B1
87
What is respiratory burst?
The production of reactive oxygen species for the killing of bacteria by immune cells
88
What is the end product of respiratory burst?
Bleach = HOCL
89
What is the first step in respiratory burst?
Oxidation of oxygen to a superoxide radical using NADPH
90
What is the mech of superoxide dismutase?
Converts superoxide radical to H2O2
91
What does myeloperoxidase do?
Converts H2O2 to bleach
92
What does bacterial catalase do?
Converts H2O2 to water and oxygen so that it cannot be used by the host to make ROIs
93
What does G6PD do in respiratory burst?
Generates more NADPH for respiratory burst using G6P
94
How do we deal with our H2O2?
Reduce it using glutathione
95
What replenishes/reduces glutathione?
NADPH
96
What is the inheritance pattern of G6PD deficiency?
X linked recessive
97
What is the clinical presentation of G6PD deficiency?
Back pain then hematuria after infection, antibiotics, fava beans.
98
What do you see in the peripheral blood smear in G6PD deficiency?
Heinz bodies | Bite cells
99
What is the problem in G6PD deficiency?
Can't reduce NADP to NADPH and therefore you can't reduce glutathione so cells are susceptible to oxidative damage
100
What is the inheritance pattern of essential fructosuria?
Auto recessive
101
What is the defect in essential fructosuria?
Defect in fructokinase
102
What are the findings of essential fructosuria?
Fructose in blood and urine | Otherwise asx
103
What is the inheritance pattern of fructose intolerance?
Auto recessive
104
What is the defect in fructose intolerance?
Defect in aldolase B that results in the accumulation of fructose-1-phosphate thereby depleting the phosphate pool. Causes inhibition of glycogenolysis and gluconeogenesis
105
What are the sx of fructose intolerance?
Hypoglycemia Jaundice Cirrhosis Vom
106
What is the treatment of fructose intolerance?
Decrease intake of fructose and sucrose
107
What is the inheritance pattern of galactokinase deficiency?
Auto recessive
108
What are the signs of galactokinase deficiency?
Infantile cataracts Lack of tracking objects Lack of development of social smile Galactose in the blood
109
What is the defect in classic galactosemia?
Absence of galactose-1-phosphate uridyltransferase that causes toxic buildup of galacitol
110
What is the inheritance pattern of classic galactosemia?
Auto recessive
111
What are the findings of classical galactosemia?
Infantile cataracts, mental retardation, failure to thrive, jaundice, hepatomegaly
112
What is the treatment for classic galactosemia?
Exclude galactose and lactose from the diet
113
Where does galactitol deposit in the body?
Lens of the eye
114
What does aldose reductase do?
Converts glucose to its alcohol form, sorbitol
115
What does sorbitol dehydrogenase do?
Converts sorbitol to fructose
116
What is the consequence of an sorbitol dehydrogenase deficiency?
Sorbitol accumulates in the cells and sets up a gradient for water to come in --> osmotic damage = cataracts, retinopathy, peripheral neuropathy
117
Which organs are most susceptible to sorbitol accumulation and why?
Schwann cells, kidneys, eyes because they only have aldose reductase - no sorbitol dehydrogenase
118
What is the problem in lactase deficiency?
Loss of a brush border enzyme
119
What are the sx?
Bloating, cramps, osmotic diarrhea
120
Who is more likely to have lactase deficiency?
Asians and blacks
121
What are the essential amino acids?
Met, Val, His, Ile, Phe, Thr, Trp, Leu, Lys
122
What are the essential glucogenic amino acids?
Met, Val, His
123
What are the essential glucogenic/ketogenic amino acids?
Ile, Phe, Thr, Trp
124
What are the essential ketogenic amino acids?
Leu, Lys
125
What are the acidic amino acids?
Asp Glu These are negatively charged and bodily pH
126
What are the basic amino acids?
Arg, Lys, His
127
What is the most basic protein?
Arg
128
Which amino acid has no charge at bodily ph?
His
129
What is the urea cycle?
Ordinarily Careless Crappers Are Also Frivolous About Urination. Ornithine + Carbamoylase to Citrulline via ornithine transcarbamoylase Then Aspartate plus ATP with Citrulline converted to argininosuccinate via argininosuccinate synthetase Argininosuccinate - Fumarate = Arginine Arginine + water = urea via arginase
130
Where does the urea cycle occur?
In the liver
131
What does the Cori cycle do?
Uses lactate from anaerobic glycolysis for gluconeogenesis
132
What is the glucose-alanine cycle?
Used as a secondary transport of ammonium from muscles | Used for gluconeogenesis during starvation
133
What other amino acid is used for transport of ammonium in the body?
Glutamate/alpha ketoglutarate
134
What is the rate limiting step in the urea cycle?
The first step using CO2, NH4, and 2 ATP to make carb amigo phosphate
135
What is the problem in hyperammonemia?
Excess NH4 results in depletion of alpha-ketoglutarate and therefore inhibits the TCA cycle so ATP production is impaired
136
What is the tx for hyperammonemia?
Limit protein in diet Benzoate or phenylbutyrate - bind amino acid and lead to excretion Lactulose to acidify the GI tract and trap NH4 for excretion
137
What are the sx of ammonia intoxication?
``` Asterixis Slurring of speech Somnolence Vomiting Cerebral edema Blurring of vision ```
138
What is the most common urea cycle disorder?
Ornithine transcarbamoylase deficiency
139
What is the inheritance pattern of ornithine transcarbamoylase deficiency?
X linked recessive
140
What is the problem in ornithine transcarbamoylase deficiency?
The body can't eliminate ammonia
141
What are the findings in ornithine transcarbamoylase deficiency?
Increased orotic acid in the urine and blood Decreased BUN Sx of hyperammonemia: asterixis, somnolence, vom, slurred speech, cerebral edema, blurred vision
142
What amino acid is epinephrine derived from?
Phenylalanine
143
What amino acid is norepinephrine derived from?
Phenylalanine
144
What amino acid is dopamine derived from?
Phenylalanine
145
What amino acid is melanin derived from?
DOPA from phenylalanine
146
What amino acid is thyroxine derived from?
Tyrosine from phenylalanine
147
What amino acid is melatonin derived from?
Serotonin from tryptophan
148
What amino acid is serotonin derived from?
Tryptophan
149
What amino acid is niacin derived from?
Tryptophan
150
What amino acid is histamine derived from?
Histidine
151
What amino acid is porphyrin derived from?
Glycine
152
What vitamin is needed for the synthesis of porphyrin?
B6
153
What amino acid is creatinine derived from?
Arginine
154
What amino acid is urea derived from?
Arginine
155
What amino acid is nitric oxide derived from?
Arginine
156
What amino acid is GABA derived from?
Glutamate
157
What amino acid is glutathione derived from?
Glutamate
158
Which vitamins are need for the synthesis of norepinephrine?
B6 and vit C
159
Which enzyme is responsible for converting dopamine to norepinephrine?
Dopamine B-hydroxylase
160
Which enzyme is responsible for converting norepinephrine to epi?
Phenylethanolamine N-methyltransferase
161
What does dopamine get broken down to by MAO and COMT?
HVA- homovanyllic acid
162
What does norepinephrine get broken down into via MAO or COMT?
VMA
163
What does epinephrine get broken down into by MAO or COMT?
Metanephrine
164
What is the inheritance pattern of phenylketonuria?
Auto recessive
165
What is the problem in phenylketonuria?
Due to a deficiency in phenylalanine hydroxylase or decreased tetrahydrobiopterin cofactor so tyrosine becomes essential and phenylalanine ketones spill over into the urine
166
What are the phenylketones?
Phenyl-acetate Phenyl lactate Phenylpyruvate
167
What are the sx of phenylketonuria?
``` Mental retardation Musty body odor Fair skin Seizures Eczema Growth retardation ```
168
What is the tx for phenylketonuria?
Decreased phenylalanine | Increased tyrosine intake
169
What is maternal PKU?
Lack of proper dietary therapy during pregnancy
170
What does maternal PKU cause in the infant?
Microcephaly Mental retardation Growth retardation Congenital heart defects
171
What is alkaptonuria?
A congenital deficiency in homogentistic acid oxidase in the degradation pathway of tyrosine to fumarate
172
What is the inheritance pattern of alkaptonuria?
Auto recessive
173
What are the findings of alkaptonuria?
Dark connective tissue Brown pigmented sclera Urine that turns black with exposure to air Debilitating arthralgias
174
What is the inheritance pattern of albinism?
Variable due to locus heterozygosity Auto recessive (deficient tyrosinase) X liked recessive (ocular)
175
What is the deficiency in albinism?
Tyrosinase - cant synthesize melanin from tyrosine Tyrosine transporters Can result from lack of migration of neural crest cells
176
What are albinos at increased risk for?
Cancer
177
What is the inheritance pattern of homocystinuria?
Auto recessive
178
What are the 3 forms of homocystinuria?
Cystathionine synthase deficiency Cystathionine synthase has decreased affinity for pyridoxal phosphate Homocysteine methyltransferase deficiency
179
What are the findings in homocystinuria?
``` Homocysteine in the urine Mental retardation Osteoporosis Tall statur Kyphosis Lens subluxation (down and in) Atherosclerosis ```
180
What is the tx for decreased affinity of cystathionine synthase for pyridoxal phosphate?
Increased B6 in the diet
181
What is the treatment for cystathionine synthase deficiency?
Decreased Met and increase cysteine, B12 and folate in the diet
182
What is cystinuria?
Hereditary defect of renal tubular amino acid transporter for cysteine, ornithine, lysine, and arginine in the PCT of the kidneys
183
What is the inheritance pattern of cystinuria?
Auto recessive
184
What is the treatment of cystinuria?
Hydration | Alkalinization of the urine
185
What is cystine?
2 cysteines connected with a disulfide bond
186
What is seen in cystinuria?
Precipitation of hexagonal crystals | Renal stag horn calculi
187
What is the defect in maple syrup urine disease?
Blocked degradation of branched amino acids (Ile, leu, Val ) due to decreased alpha-ketoacid dehydrogenase (B1)
188
What is the inheritance pattern of maple syrup urine disease?
Auto recessive
189
What are the sx of maple syrup urine disease?
Severe CNS defects Mental retardation Death
190
What is the effect of maple syrup urine disease?
Increased alpha-ketoacid in the blood, especially leu
191
What is the inheritance pattern of Hartnup disease?
Auto recessive
192
What is the defect in Hartnup disease?
Defective neutral amino acid transporter on renal and intestinal epi cells that causes increased Trp excretion and decreased absorption from the GI.
193
What does Hartnup disease cause?
Pellagra - dermatitis, dementia, diarrhea, death
194
What else causes pellagra?
B3 deficiency
195
What is the structure of glycogen?
Branches have alpha (1,6) bonds | Linkages have alpha (1,4) bonds
196
What happens to glycogen during glycogenolysis?
It is broken down to be used in glycolysis | Glycogen --> glucose 1 phosphate --> glucose 6 phosphate --> glycolysis
197
Where is glycogen stored?
In the liver
198
What activates glycogen phosphorylase kinase?
Protein kinase A/calcium/calmodulin in muscle
199
What happens when insulin is high?
Receptor tyrosine kinase dimerizes and activates protein phosphatase which inactive glycogen phosphorylase kinase
200
What is the enzyme that converts glucose-1-phosphate to UDP-glucose?
UDP-glucose pyrophosphorylase
201
What converts UDP-glucose into glycogen?
Glycogen synthase
202
What enzyme converts glycogen back into glucose-1-phosphate?
Glycogen phosphorylase
203
What is the missing enzyme in Von Gierke's disease?
Glucose-6-phosphatase
204
What are the findings in Von Gierke's disease?
Sever fasting hypoglycemia Increased glycogen in the liver Increased lactic acid in the blood Hepatomegaly
205
What is the deficient enzyme in Pompe's disease?
Alpha-1,4-glucosidase
206
What are the findings in Pompe's disease?
Cardiomegaly Systemic findings leading to an early death Pompe's trashes the pump: heart, liver, muscles
207
What is the deficient enzyme in Cori's disease?
De branching enzyme: alpha-1,6-glucosidase
208
What are the findings of Cori's disease?
Milder sx of type I (Von Gierke's) with normal levels of blood lactate
209
What is the deficient enzyme in McArdle's?
Skeletal muscle glycogen phosphorylase
210
What are the findings in McArdle's?
Increased glycogen in muscle Myoglobinuria aft exercise Muscle cramps
211
What are the 4 glycogen storage diseases we have to know?
``` Very Poor Carbohydrate Metabolism Von Gierke's - type I Pompe's -type II Cori's -type III McArdle's - type V ```
212
What are the inheritance patterns of these 4 glycogen storage diseases?
Auto-recessive
213
What is the deficient enzyme in Fabry's disease?
Alpha-galactosidase A
214
What is the accumulated substrate in Fabry's disease?
Ceramics trihexoside
215
What is the inheritance pattern of Fabry's?
X linked recessive
216
What are the findings of Fabry's?
Peripheral neuropathy of the hands/feet Angiokeratomas CV/renal disease
217
What is the most common lysosomal storage disease?
Gaucher's -- auto recessive
218
What is the deficient enzyme in Gaucher's?
Glucocerebrosidase
219
What is the accumulated substrate in Gaucher's?
Glucocerebroside
220
What are the findings in Gaucher's?
HSM Aseptic necrosis of the femur Bone crises Gaucher's cells = macs that look like crumpled tissue pap
221
What is the deficient enzyme in Niemann-Pick disease?
Sphngimyelinase
222
What is the accumulated substrate in Niemann-Pick's?
Sphingomyelin
223
What are the findings in Niemann-Pick's?
Progressive neurodegeneration HSM Cherry-red spot in macula Foam cells
224
What is the deficient enzyme in Tay-Sachs disease?
Hexosaminidase A
225
What is the accumulated substrate in Tay Sachs?
GM2 ganglioside
226
What are the findings in Tay Sachs?
Progressive neurodegeneration Developmental delay Cherry red spot on macula Lysosomes with onion skin
227
What is the deficient enzyme in Krabbe's disease?
Galactocerebrosidase
228
What is the accumulated substrate in Krabbe's?
Galactocerebroside
229
What are the findings in Krabbe's disease?
Peripheral neuropathy Developmental delay Optic atrophy Globoid cells
230
What is the defient enzyme in Metachromatic leukodystrophy?
Arylsulfatase A
231
What is the accumulated substrate in Metachromatic leukodystrophy ?
Cerebroside sulfate
232
What are the findings of Metachromatic leukodystrophy?
Central and peripheral demyelination Ataxia Dementia
233
What is the deficient enzyme in Hurler's syndrome?
Alpha-l-iduronidase
234
What are the accumulated products in Hurler's syndrome?
Heparan sulfate, dermatan sulfate
235
What are the findings in Hurler's syndrome?
``` Developmental delay Gargoylism Airway obstruction Corneal clouding HSM ```
236
What is the deficient enzyme in Hunter's syndrome?
Iduronate sulfatase
237
What are the accumulated products in Hunter's syndrome?
Heparan sulfate | Dermatan sulfate
238
What are the findings in Hunter's syndrome?
Mild Hurler's Aggressive behavior No corneal clouding
239
Which lysosomal storage disease are X linked?
Fabry's and Hunter's
240
What is the inheritance pattern of the other lysosomal storage diseases?
Auto recessive
241
What is carnitine deficiency?
Inability to transport LCFAs into mitochondria --> toxic buildup
242
What are the sx of carnitine deficiency?
Weakness Hypotonia Hypoketotic hypoglycemia
243
Where does FA degradation occur?
In the mitochondrial matrix
244
Where does FA synthesis happen?
In the cytoplasm
245
What is the main regulation on beta oxidation of FAs?
Malonyl-CoA inhibits carnitine acyl transferase
246
What is the result of FA degradation?
Acetyl-CoA groups for TCA cycle or ketone body production
247
Which vitamin is used during fatty acid synthesis?
B7 -biotin to carboxylate acetyl-CoA to become malonyl-CoA
248
Why do we make ketone bodies?
Because oxaloacetate becomes depleted during long periods of starvation or after alcohol so TCA cycle is stalled and glucose and FAs are shunted toward making ketone bodies
249
What are the ketone bodies made?
Acetoacetate | B-hydroxybutyrate
250
What is the rate limiting enzyme for ketone body production?
HMG CoA synthase
251
What is used for energy during the first seconds of exercise?
Stored ATP and creating phosphate
252
What kind of metabolism is going on during prolonged exercise?
Aerobic metabolism and FA oxidation
253
How much energy does 1 gram of protein provide?
4 kcal
254
How much energy does 1 gram of Fat provide?
9 kcal
255
How long do glycogen reserves last?
1 day
256
What are the major mechanisms that maintain blood glucose levels during days 1-3 of starvation?
Hepatic glycogenolysis Muscle and liver use FAs Hepatic gluconeogenesis from lactate and alanine, FAs and TAGs
257
What is the major source of energy after 3 days of starvation?
Ketone bodies
258
What is the source of energy after ketone body production is depleted?
Vital proteins --> organ failure, death
259
What are ketone bodies made out of?
Acetyl-CoA --> HMG CoA
260
What is chokes too made out of?
HMA CoA
261
What enzyme esterifies 2/3 of plasma cholesterol?
Lecithin-cholesterol acyl transferase (makes HDL)
262
What does pancreatic lipase do?
Degrades dietary TGs in small intestine
263
What do lipoprotein lipase do?
Degrades TGs circulating in chylomicrons and VLDL
264
What does hepatic TG lipase do?
Degrades TG remaining in IDL
265
What does hormone-sensitive lipase do
Degrades TGs stored in adipocytes
266
What does cholesterol ester transfer protein do
Mediates transfer of cholesterol esters to lipoprotein particles (VLDL, IDL, LDL)
267
What does apolipoprotein E do?
Mediates remnant uptake in all transporters except LDL
268
What does apolipoprotein A-I do?
Activates LCAT
269
What does apolipoprotein C-II do
Lipoprotein lipase cofactor | Helps degrade from HDL, VLDL, chylomicrons
270
What does apolipoprotein B48 do?
Mediates chylomicron secretion
271
What does apolipoprotein B100 do?
Binds LDL receptor
272
What does LDL do?
Delivers cholesterol from liver to tissues.
273
How is LDL taken up by target cells?
Via receptor mediated endocytosis
274
How is LDL formed?
By hepatic lipase modification of IDL in peripheral tissue
275
What do chylomicrons do?
Deliver dietary TGs to peripheral tissue | Delivers cholesterol to liver
276
What are chylomicrons secreted by?
Intestinal epithelial cells
277
What does VLDL do?
Delivers hepatic TGs to peripheral tissue | Secreted by the liver
278
How is IDL formed?
During degradation of VLDL
279
What does IDL do?
Delivers triglycerides and cholesterol to liver
280
What does HDL do?
Delivers cholesterol from periphery to liver | Acts as a repository for apoC and apoE
281
Where is HDL secreted from?
Liver and intestines
282
What is the inheritance pattn of I-hyperchylomicronemia?
Auto recessive
283
What is the defect in I-hyperchylomicronemia?
Deficient LPL or apoC-II causes pancreatitis, HSM, eruptive/pruritic xanthomas
284
What is elevated in the blood in I-hyperchylomicronemia?
Chylomicrons, TGs, cholesterol
285
What is the inheritance pattern of IIa-familial hypercholesterolemia?
Auto dominant
286
What is the problem in IIa- familial hypercholesterolemia?
Absent or decreased LDL receptors that causes accelerated atherosclerosis, tendon (Achilles) xanthomas, corneal areus
287
What is elevated in the blood in IIa-familial hypcholesterolemia?
LDL, cholesterol
288
What is the inheritance pattern of IV-hypertriglyceridemia?
Auto Dom
289
What is the problem in IV-hypertriglyceridemia?
Hepatic overproduction of VLDL that causes pancreatitis
290
What is elevated in the blood in IV-hypertriglyceridemia?
VLDL, TGs
291
What is the inheritance pattern of abetalipoproteinemia?
Auto recessive
292
What is the mutation in abetalipoproteinemia?
Mutation in microsomal transfer protein gene so you have decreased levels of apoB48 and B100 so there is decreased chylomicron and VLDL synthesis and secretion
293
What are the findings of abetalipoproteinemia?
``` Failure to thrive Steatorrhea Acanthocytosis Ataxia Night blindness ```
294
What do you see on bx of intestines?
Lipid accumulation within enterocytes due to inability to export lipid as chylomicron
295
What enzyme converts phenylalanine to tyrosine?
Phenylalanine hydroxylase + BH4 cofactor
296
What enzyme reduces BH2 to BH4?
Dihydropteridine reductase (using NADP-->NADPH)
297
What is BH4 used in?
The synthesis of tyrosine, DOPA, serotonin and nitric oxide
298
What enzyme converts tyrosine to DOPA?
Tyrosine hydroxylase + BH4
299
What enzyme converts DOPA to dopamine?
DOPA decarboxylase + B6
300
What enzyme converts dopamine to norepinephrine?
Dopamine b-hydroxylase + Vit C
301
What enzyme converts norepinephrine to epi?
Phenylethanolamine n-methyltransferase + SAM
302
What is SAM?
ATP+methionine
303
What is SAM used for?
Transferring methyl groups
304
What drug inhibits dopa decarboxylase?
Carbidopa
305
What stimulates phenylethanolamine n-methyltransferase?
Cortisol
306
What is malignant/atypical PKU?
Deficiency in dihydropteridine reductase - no BH4 Decreased tyrosine, dopa, serotonin, nitric oxide. May see hyperprolactinemia
307
What does fructose-2,6-bis phosphatase do?
Converts fructose-2,6-phosphate to fructose-6-phosphate
308
What does fructose-2,6-bisphosphate stimulate?
Phosphofructokinase 1(glycolysis)
309
When is fructose-2,6-bisphosphate active?
In the fasting state
310
What does phosphofructokinase 2 do?
Converts fructose-6-phosphate to fructose-2,6-phosphate
311
What does aldose reductase do in the galactose pathway?
Converts galactose to galactitol
312
When is aldose reductase active in the galactose pathway?
In classic galactosemia and galactokinase deficiency
313
What does galactose-1-phosphate uridyltransferase do?
Converts galactose-1-phosphate to glucose-1-phosphate with the help of 4-epimerase and UDP-glucose
314
What does galactokinase use in its reaction?
ATP
315
What enzyme converts H2O2 to two molecules of water
Glutathione peroxidase
316
What does fructokinase do?
Converts fructose to fructose-1-p
317
What does aldolase B do?
Converts fructose-1-p to dihydroxyacetone-P and aglyceraldehyde
318
What does triose kinase do?
Converts glyceraldehyde to glyceraldehyde-3-p
319
How does glyceraldehyde become glycerol?
By oxidizing NADH to NAD
320
Which enzymes are going to be affected most in alcoholics?
Alpha-ketoglutarate dehydrogenase Pyruvate dehydrogenase Transketolase Branched chain amino acid dehydrogenase
321
What are the sx of dry beri beri?
Polyneuritis | Symmetrical muscle wasting
322
What are the sx of wet beri beri?
High output heart failure, edema
323
What can cause pellagra?
``` Hartnup disease Malignant carcinoid syndrome INH Corn diet Alcoholism ```
324
Which enzyme of the TCA cycle is most effected by B2 deficiency?
Succinate dehydrogenase
325
What enzymes are effected by a B6 deficiency?
Alanine aminotransferase (pyruvate to alanine) Delta-levulinic acid synthase (glycine + succinate) Glutamate --> GABA Tryptophan --> niacin Histidine --> histamine Dopa --> dopamine Homocysteine to cystathionine
326
What enzyme would be most affected by a biotin deficiency?
Pyruvate carboxylase (pyruvate to oxaloacetate) Acetyl-CoA carboxylase (acetyl CoA to malonyl CoA) Propionyl CoA carboxylase (propionyl CoA to methyl malonyl CoA
327
Why does methyl malonyl CoA build up if there is a B12 deficiency?
Because b12 is a cofactor in the conversion of methyl malonyl CoA to succinyl CoA
328
What does alanine aminotransferase do?
Transfers amino groups from alanine to alpha ketoglutarate (to become glutamate) in the muscle and liver --> urea
329
What enzyme used ATP in the urea cycle?
Arginosuccinate synthetase
330
What is the enzyme that converts homocysteine to methionine?
Homocysteine methyltransferase using B12
331
How is cystathionine synthesized?
From homocysteine + serine by cystathionine synthase and B6
332
What activates glycogen phosphorylase kinase?
Calcium/calmodulin Activated in the fasting state when glucagon binds G protein receptor and causes signal transduction by increase in adenylyl cyclase and camp --> increase protein kinase A
333
What does protein kinase A do?
Phosphorylation glycogen phosphorylase kinase to become active
334
What does glycogen phosphorylase kinase do?
Phosphorylates glycogen phosphorylase to become active for glycogenolysis
335
What activates protein phosphatase?
Insulin
336
What does protein phosphatase do?
Dephosphorylates glycogen phosphorylase kinase and glycogen phosphorylase to become inactive
337
What enzyme converts acetoacetate to acetoacetyl CoA in ketogenesis?
Thiophorase
338
What enzyme converts acyl CoA to acetyl CoA groups?
Acyl CoA dehydrogenase in fatty acid oxidation with the help of B2
339
What does fatty acid CoA synthetase do?
Coverts fatty acids and CoA to acyl-CoA to be transported into the mito
340
What does ATP citrate lyase do?
Converts citrate to acetyl CoA in fatty acid synthesis
341
Which enzyme is decreased in a deficiency of Riboflavin?
Succinate dehydrogenase

Biochem First aid (3 decks)

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