Metabolism disorders

Question 1

essential fructosuria

Answer 1

no big deal, AR, benign

lack FRUCTOKINASE, but that’s okay because Fructose can get converted to G6P by hexokinase, or you just pee it out

Question 2

fructose intolerance

Answer 2

deficiency: ALDOLASE B

causes a build up of F-1-P –> depletes usable phosphate –> depletes ability to make ATP –> can’t do gluconeogenesis or glycogenolysis + build of of AMP then gets shunted towards UMP pathway and gets turned into Uric acid

Question 3

levels of metabolites in fructose intolerance

Answer 3

high F1P, low useable P, high uric acid

Question 4

essential amino acids

Answer 4

PVT TIM HALL

phenyl, valine, threonine
tryp, isoluec, meth
histidine, arginine, lysine, leucine

Question 5

aldolase B deficiency

Answer 5

FRUCTOSE metab

Question 6

uridyltransferance deficiency

Answer 6

GALACTOSE metab

Question 7

galactokinase deficiency

Answer 7

messed up galactokinase

you get a build up of galactitol –> cataracts, failure to track

Question 8

classic galactosemia

Answer 8

this is a problem. You lack uridyltransferase –> meaning you can’t metabolize Galactose-1-phosphate –> build up of unusable phosphate products –> leads to decreased gluconeogensis/ glycogenolysis

Question 9

hartnups

Answer 9

defect of neutral aa transporters in gut and urine

B3 deficiency: pellagra –> diarrhea, dermatitis, dementia

Question 10

hyperammonia disrupts the _______ cycle in _______ (brain)

Answer 10

glutamine- glutamate cycle, astrocytes

this is due to astrocyte swelling (hyperosmoloartiy), impaired glutamine release

Question 11

infection seen in classic galactosemia?

Answer 11

e. coli sepsis in neonates

Question 12

NAD+ is involved in what types of reactions? NADH?

Answer 12

NAD+ = catabolic

NADH= anabolic

NADH is longer, its built up. NAD+ is shorter, its been broken down.

Question 13

NADH is involved in what specific reactions?

Answer 13

resp burst
anabolic reactions –> FATTY ACID, CHOLESTEROL
cytp450
glutathione reductase

Question 14

how does the body make glucose during starvation?

Answer 14

glycogenolysis -12-18 hours

then, gluconeogenesis (oxaloacetate –> PEP)

Question 15

basic steps of gluconeogenesis

Answer 15

Pyruvate –> pyruvate CARBOXYLASE –> oxaloacetate –> pep-ck –> PEP, and then moves on up to glucose

Question 16

primary carnitine deficiency (mech)

Answer 16

causes hypoketotic hypoglycemia –> defect in beta oxidation of FA

carnitine shuttle is used to shuttle fatty acids from cytoplasm to mitochondria to break down into ketone bodies and go into TCA

Question 17

signs of primary carnitine deficiency

Answer 17

cardiomyopathy, elevated creatine (weakness, decrease carnitine, NO KETONES + HYPOGLYCEMIA

Question 18

can you use triglycerides to make glucose?

Answer 18

yes. Glycerol stored in adipose tissue can be broken down by GLYCEROL KINASE to yield DHAP through G3P

Question 19

how does acetyl co a regulate the fate of pyruvate?

Answer 19

HIGH acetyl co diverts pyruvate to PYRUVATE DECARBOXYLASE for gluconeogenesis

when levels are low, it will upregulate PDH complex in order to keep energy up for cell

Question 20

hypoketotic hypoglycemia

Answer 20

problem with beta oxidation of fatty acids

Question 21

what cofactors are represented by the mnemonic “TLC for Nancy”? What reactions are they necessary for?

Answer 21

thiamine (b1), Lipoic acid (inhib by arsenic), Co-A, FAD (b2), NAD (b3)

Pyruvate Dehydrogenase Complex
aKetoglutarate
BCKDC (MSUD) –> supplmenet with THIAMINE!

Question 22

Biotin (B7) is used as a cofactor for what type of reactions?

Answer 22

Carboxylase reactions
Pyruvate –> oxalo
Acetly CoA –> malonyl (fatty acid synth)
Proionyl CoA –>methylmalonyl

Question 23

propionic acidemia

Answer 23

lack PROPIONYL COA CARBOXYLASE
converts prpionyl CoA –> methylmalonyl CoA (goes into TCA as succinyl CoA via B12)

val, isoluece, threonine, methionine, odd chain fatty acids enter here

Question 24

when does propionic acidemia present? how?

Answer 24

presents in the first few weeks of life with lethargy, poor feeding, vomitting
high ketones, hypoglycemia, hypotonia