amino acid degradation

Question 1

pyruvate family

Answer 1

alanine, serine, glycine

Question 2

alanine breakdown

Answer 2

alanine to pyruvate
E: alanine aminotransferase (ALT)
alpha-KG to glutamate

Question 3

serine breakdown

Answer 3

serine to pyruvate
releases unstable aminoacrylate
E: serine dehydratase (SDH)
releases H2O
requires B6 PLP complex (vit B6)

Question 4

glycine breakdown 2 pathways

Answer 4

1) glycine to serine, then to pyruvate

2) glycine degraded directly

Question 5

glycine to serine

Answer 5

glycine to serine
E: serine hydroxymethyltransferase (SHMT)
THF to N5, N10 - Methylene THF + H2O
requires B6

Question 6

glycine cleavage system

Answer 6

Glycine breakdown
E: glycine oxidase in reverse
requires PLP and lipoic acid

Question 7

what is PLP?

Answer 7

active form of vit B6

Question 8

asparagine breakdown

Answer 8

1) asparagine to aspartate
E: asparaginase
releases NH4+
2) aspartate + alpha-KG to glutamate + oxaloacetate
E: aspartate aminotransferase (AST)

Question 9

which 2 amino acids yield oxaloacetate?

Answer 9

Aspartate (Asp-D) and Asparagine (Asn-N)

Question 10

alpha-KG family

Answer 10

glutamate and glutamine

Question 11

glutamine breakdown

Answer 11

1) glutamine to glutamate
E: glutaminase
H2O to NH4+
2) Glutamate to alpha-KG
E: glutamate dehydrogenase (GDH)
NADP+ to NADPH + NH4+

Question 12

glutamate breakdown

Answer 12

glutamate to alpha-KG
E: glutamate dehydrogenase (GDH)
NADP+ to NADPH + NH4+

Question 13

succinyl-CoA family

Answer 13

Methionine, Isoleucine, and Valine

Question 14

arginine and proline

Answer 14

get broken down, they’re being processed

Question 15

methionine breakdown

Answer 15

methionine can produce cysteine then propionyl-CoA

SAM is used as a methyl donor

Question 16

BCAT

Answer 16

branched-chain amino acid aminotransferase

Question 17

leucine breakdown

Answer 17

1) leucine to alpha-ketoisocaproate
E: BCAT
alpha-KG to G
2) BCKDH, fatty acid oxidation
to become acetoacetate and acetyl-CoA

Question 18

phenylalanine/tyrosine

Answer 18

1) phenylalanine to tyrosine
E: phenylalanine-4-monooxygenase
2) tyrosine to rho-hydroxy-phenylpyruvate
E: tyrosine transaminase
alpha-KG to Glu
then dioxygenases to acetoacetate + fumarate

Question 19

tyrosine synthesis

Answer 19

from phenylalanine

Question 20

cysteine synthesis

Answer 20

from methionine

Question 21

glutmate

Answer 21

from glutamine and vice versa

Question 22

serine and glycine role

Answer 22

1 carbon donation (they form pyruvate!)

Question 23

amino acid products

Answer 23

1) physiologically active amines
2) glutathione (management of S-S bonds)
3) heme
4) NAD+

Question 24

glutamate produces

Answer 24

GABA and Histamine

Question 25

tyrosine produces

Answer 25

Catecholamines

EX: Dopa, Dopamine, Norepinephrine –> (uses SAM) Epinephrine

Question 26

glycine produces

Answer 26

heme