Biochem Flashcards
Only secondary AA
proline
Glucogenic essential AA
Met
Val
His
Ketogenic essential AA
Leu
Lys
Glucogenic/Ketogenic essential AA
Isoleucine
Phenylalanine
Threonine
Tyrptophan
Charge of acidic AA at body pH
negative
Acidic AA
Asp
Glu
Charge of basic AA at body pH
Positive
His has NO charge
Basic AA
Arg
Lys
His
(arg and lys are high in histones to bind negatively charged DNA)
Which AAs have 3 titratable protons?
Acidic AA (Asp, Glu)
Basic AA (Arg, Lys, His)
Cysteine
Tyrosine
Only urea cycle disorder that is X-linked recessive
ornithine transcarbamylase deficiency
AA used NO, Creatinine, Urea
Arginine
AA used to make GABA and Glutathione
Glutamate
AA used to make Heme
GLycine
AA used to make Histamine
Histidine
AA used to make Serotonin, Melatonin, Niacin, and NAD+/NADP+
Tryptophan
AA used to make Thyroxine, Melanin, Dopamine, NE, and Epi
Phenylalanine
What is required in the step from phenylalanine to tyrosine?
BH4 (regenerated from BH2 by dihydropiopterin reductase)
What is required in the step from Tyrosine to Dopa?
BH4
What is required in the step from dopa to Dopamine?
Vitamin B6
What is required in the step from Dopamine to NE?
Vitamin C (Dopamine hydoxylase)
What is required in the step form NE to Epi?
SAM
What vitamin is needed to synthesize niacin form tryptophan?
B6
What is needed to make 5-HT from Tryptophan?
BH4 and B6
What other amino acids need B6 to make their products?
- Phenalanine (Dopa to DA)
- Tryptophan (to niacin and to 5-HT)
- Histidine (to histamine)
- Glutamate (to GABA)
- Glycine (to porphyrin)
What is needed to make NO from arginine?
BH4
What enzyme is deficient in PKU?
Phenylalanine hydroxylate
or tetrahydrobiopterin cofactor
What builds up in PKU?
phenylalanine
How do you treat PKU?
low phenylalanine, high tyrosine diet
What enzyme is deficient in Alkaptonuria?
Homogentisate oxidase
What builds up in alkaptonuria?
Homogentisic Acid (toxic to joints)
What are the 3 causes of homocystinuria?
- Cysthathionine synthase deficiency
- Decreased affinity of cystathionine synthase for pyridoxal phosphate
- Homocysteine methyltransferase deficiency
How do you treat cystathionine synthase deficiency?
Methionine will be high and cysteine will be low, so decrease methionine and increase cysteine and B12/folate in the diet
How do you treat a decreased affinity of cystathionine synthase for pyridoxal phosphate
Give extra B6 and increase cysteine in the diet
How do you treat a homocysteine methyltransferase deficiency?
Methionine will be low, so increase it in the diet
What causes cystinuria?
defect in AA transporter in renal PCT for Cysteine, Ornithine, Lysine and Arginine (COLA)
What causes MSUD?
decreased alpha-ketoacid dehydrogenase (B1= thiamine is cofactor)