铜（II）碳酸酐酶与HCO₃⁻/CO₂系统的研究

Investigation of the system copper(II) carbonic anhydrase and HCO3-/CO2.

作者信息

Bertini I, Canti G, Luchinat C, Borghi E

出版信息

J Inorg Biochem. 1983 Jun;18(3):221-9. doi: 10.1016/0162-0134(83)85004-1.

Abstract

Copper(II) substituted human and bovine carbonic anhydrases B in the presence of bicarbonate have been investigated in solution through water-solvent proton nuclear magnetic resonance (nmr) at variable magnetic fields. HCO3-, contrary to all the other monoanionic inhibitors, partially reduces the water proton relaxation rates. This has been accounted for on the basis of the availability within the active cavity of two coordination positions partially overlapping. 13C-nmr measurements on both CO2 and HCO3- confirm that HCO3- binds the metal, whereas CO2 interacts with the paramagnetic center at nonbonding distance. The upper limit for the CO2 in equilibrium HCO3- interconversion has been estimated to be 10 sec-1.

摘要

在可变磁场下，通过水-溶剂质子核磁共振（nmr）对存在碳酸氢盐时铜（II）取代的人碳酸酐酶B和牛碳酸酐酶B进行了溶液研究。与所有其他单阴离子抑制剂相反，HCO₃⁻会部分降低水质子弛豫速率。这是基于活性腔内两个部分重叠的配位位置的可用性来解释的。对CO₂和HCO₃⁻的¹³C-nmr测量证实，HCO₃⁻与金属结合，而CO₂在非键合距离处与顺磁中心相互作用。HCO₃⁻与CO₂平衡互变的上限估计为10秒⁻¹。