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Flashcards in metabolism Deck (22):
1

homogentisate oxidase deficiency

alkaptonuria

benign disorder of tyrosine metabolism (blocks metabolism of phenylalanine and tyrosine at the level of homogentisic acid--> prevents conversion of tyrosine to fumarate)

pigment forming homogentisic acid accumulates in tissue

2

what is diminished in hyperammonemia of hepatic encephalopathy or urea cycle enzyme deficiencies?

alpha ketoglutarate and glutamate (glutamine is high)

3

B12 deficiency

can lead to a folate trap--> impaired synthesis of methionine and sometimes homocysteinuria (because reaction pushed in the other direction)

4

G6PD deficiency

cant complete HMP shunt, so decreased NADPH concentration; decreased NADPH in RBCs--> decreased glutathione reduction--> less detoxification of free radicals and peroxides--> hemolytic anemia

5

galactose-1-phosphate uridyltransferase deficiency

classic galactosemia; damaged caused by accumulation of toxic substances (not just galacitol)

6

HGPRT deficiency?

defective purine salvage

7

medium chain acyl-CoA dehydrogenase deficiency

disorder of fatty acid oxidation --> cant break down fatty acids into acetyl-CoA--> accumulation of 8-10 carbon fatty acyl carnitines in the blood and hypoketotic hypoglycemia

8

fructokinase deficiency

essential fructosuria

ALTERNATE METABOLIC PATHWAY: increase of fructose-6-phosphate (via hexokinase activity)--> metabolized in glycolytic pathway or converted to G6P

9

lipoprotein lipase deficiency

familial dyslipidemia type I- hyperchylomicronemia

increased chylomicrons, triglycerides, cholesterol

10

LDL receptor deficiency or defect

familial dyslipidemia type IIa- family hypercholesterolemia

increased LDL, cholesterol

11

hepatic overproduction of VLDL

familial dyslipidemia type IV- hypetriglyceridemia

increasedV LDL, triglycerides

12

aldolase B deficiency

fructose intolerance

increased concentration of fructose-1-phosphate--> decreased available phosphate and inhibition of glycogenolysis and gluconeogenesis; sxs after consuming fruit, juice or honey

13

galactokinase deficiency

galacitol accumulates in the blood if galactose is present; mild condition

14

cystathione synthase deficiency

homocystinuria

15

decreased cystathionine synthase affinity for pyridoxal phosphate

homocystinuria

16

homocysteine methyltransferase deficiency

homocystinuria

17

systemic primary carnitine deficiency

inherited defect in transport of long-chain fatty acids into the mitochondria--> toxic accumulation

18

alpha-ketoacid dehydrogenase

MSUD

blocked degradation of branched amino acids (isoleucine, leucine, valine)

19

deficiency

pathophys

20

phenylalanine hydroxylase deficiency

PKU


excess phenylalanine--> excess phenylketones in urine

21

PDH complex deficiency?

pyruvate can't enter glycolysis/TCA cycle so is converted to lactate and alanine instead

22

n-acetylglutamate synthase deficiency

required cofactor for carbamoyl phosphate synthetase I--> can't do urea cycle--> hyperammonemia