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CH1012
Zn-ANHYDRASE
Carbonic anhydrase
- enzyme catalyst
CO2(g) + H2O(l)           H2CO3(aq)    D  HCO3-(aq) 
®
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Respiration:
Zn2+ a Lewis
acid activates
H2O so that
it can attack
CO2 in the
active site of
the enzyme.
• 70% of CO2 ends up transferred to lungs
as HCO3-, hemoglobin 20% See BLB: P270
histidines