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.
|Titolo:||Investigation of the system copper(II) carbonic anhydrase and HCO3-/CO2|
|Parole Chiave:||Carbonic Anhydrases; Animals; Cattle; Bicarbonates; Humans; Isoenzymes; Copper; Mathematics; Magnetic Resonance Spectroscopy; Carbon Dioxide; Binding Sites|
|Settore Scientifico Disciplinare:||Settore BIO/14 - Farmacologia|
|Data di pubblicazione:||giu-1983|
|Digital Object Identifier (DOI):||10.1016/0162-0134(83)85004-1|
|Appare nelle tipologie:||01 - Articolo su periodico|