Page 188 - Color Atlas of Biochemistry

Protein Metabolism 179

A. Transamination and deamination B. Mechanism of transamination
H
Amino Lysine residue
acid OOC C R
O O O O
C a C NH 3 Enzyme

H N C H O C N H
3
H C
R 1 R 1 H Aldimine 2
O
Amino acid 1 Oxoacid 1 OOC C R O
Pyridoxamine P
H N PLP phosphate H N C H H C N
3
3
1.
O H
O O O O O PLP (Aldimine 1)
C C P
H C N
3
O C b H N C H
3
R 2 R 2 2. H Aldimine 2
Oxoacid 2 Amino acid 2 Rearrangement
1. Transamination

Imino acid OOC R
O O O O C Ketimine
C a C
N
H CH
H N C H H N C 2
3
2
O
R 2 R 2 O
N A N A
Amino acid P P b H O H C N P
2
3
NH 2
H
CH 2
3. H O H
2
O O HO
NH C O
4
P
Oxoacid O C H C N
3
R 2 OOC C R H 4.
2. Oxidative deamination Oxoacid O Pyridoxamine-P
C. NH metabolism in the liver
3
Alanine trans-
From Ala Gln From 1 aminase [PLP]
2.6.1.2
the
the 3
blood blood
Glu 2 Aspartate trans-
aminase [PLP]
NH 3 2.6.1.1
A
1 N 3 Glutaminase
Asp 3.5.1.2
Pyr 4 Urea cycle 4 Glutamate
dehydrogenase
1.4.1.2
2
2
2-OG
bio-
Urea cycle,
NH 3 Transamination
syntheses
A
N Oxidative
deamination
OAA
Hydrolytic
deamination

Koolman, Color Atlas of Biochemistry, 2nd edition © 2005 Thieme
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