Protein And AA Metabolism Flashcards
1
Q
Hyperhomocysteinemia and homocystinuria
A
- Vitamin B6,9,12 deficiencies
- Genetic defects in cystathionine B-synthase
- Effects eyes, skeletal, CNS, vascular
- Risk factor in atherosclerotic heart disease and stroke
- Eye lens dislocation, osteoporosis and mental retardation
- Vitamin supplementation can normalize plasma homocysteine levels in some cases
2
Q
Maple Syrup Urine Disease
A
- Deficient branch chain a-keto acid DH complex (BCKD)
- Results in branched chain ketoaciduria
- Branch chain give hallmark maple syrup smell
- toxic effect on brain function and mental retardation eventually
3
Q
Phenylketonuria (PKU)
A
- defect in phenylalanine hydroxylase (PAH)
- Phe converted to phenylpyruvate then phenyllactate (cause of musty odor) and phenylacetate
- Severe impairment of brain function
4
Q
Secondary PKU
A
- Results from tetrahydrobiopterin deficiency (cofactor of phenylalanine hydroxylase)
- defects in synthesis or regeneration of BH4
5
Q
Trp derivatives
A
Serotonin —> Melatonin
Niacin —> NAD(P)+
6
Q
Tyr derivatives
A
Dopamine —> norepinephrine —> epinephrine
Thyroid hormones
Melanin
7
Q
Ser derivatives
A
Ach
8
Q
Glu derivatives
A
GABA
9
Q
Albinism is caused by defect in what enzyme
A
Tyrosinase
10
Q
Which step in the urea cycle involves fumarate production
A
Argininosuccinate to arginine via argininosuccinate lyase
11
Q
What type of diet increases urea production/ what diet will decrease production
A
High protein will increase
High carb will decrease
12
Q
What 3 amino acids make creatine
A
Arg
Gly
Met
13
Q
Carbamoyl phosphate synthetase is stimulated by what
A
NAG
14
Q
Arginase is inhibited by what
A
Ornithine
