Page 336 - Color Atlas of Biochemistry

Kidney 327

A. Proton secretion

Blood plasma Urine
From the
Tubule cell final urine
CO 2 CO 2

H O H O HCO 3
2
2
CO 2
1 Carbonate dehydratase
2
4.2.1.1 [Zn ] 1

2 Na /K -exchanging ATPase
3.6.1.37
1

H H
Secondary active
HCO 3 HCO 3 transport of H

A
PP
P

3Na 3Na Na Na
2
2K 2K
A
PPP

B. Ammonia excretion

Glutamine Glutamine

H O Ala
2
Ser
Amino acid Gly
with the highest 3 Asp Diffusion
plasma
concentration

NH 3 NH 3

Glutamate Glutamate H H

N A H O
2
NH 4 NH 4
4

N A
2-Oxoglutarate
Excretion of
30 – 50 mmol/day
3 Glutaminase 3.5.1.2
Tricarboxylic
4 Glutamat- acid cycle
Dehydrogenase 1.4.1.2

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