Hydrogen bonds and the catalytic mechanism of human carbonic anhydrase II.
A new model for catalysis of human carbonic anhydrase II is suggested. The model is based on the X-ray structure of the hydrogen bond network in the catalytic site. The outer part of the network is proposed to adjust the p K(a) of the catalytic site to the experimentally observed value of about 7. The inner part of the network is proposed to become a low-barrier hydrogen bond network in the transition state. The energy released in forming the low-barrier hydrogen bond network is used to catalyse the interconversion of CO(2) and HCO(3)(-). The suggested molecular mechanism is consistent with the generally accepted kinetic scheme for human carbonic anhydrase II.
Thoms
Silke
S
Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, D-27515, Germany. sthoms@awi-bremerhaven.de
D024402:Carbonic Anhydrase II / Q000378:metabolism*; D002384:Catalysis; D006801:Humans; D006859:Hydrogen / Q000378:metabolism*; D008956:Models, Chemical
D006859:Hydrogen; D024402:Carbonic Anhydrase II