Abstract
Co (III)-bovine carbonic anhydrase was reduced by L-ascorbic acid with recovery of the enzyme activity. The rate determined by following the increase in the absorbance at 640 nm (characteristic absorption of Co (II)-bovine carbonic anhydrase) was completely consistent with that determined from the recovery of the esterase activity. This result indicates that the recovery of the enzyme activity with L-ascorbic acid was caused by the reduction of a cobalt ion in the enzyme from Co (III)-bovine carbonic anhydrase to Co (II)-bovine carbonic anhydrase by L-ascorbic acid. The rate of the reduction of Co (III)-bovine carbonic anhydrase has a first-order dependence on the concentrations of both L-ascorbic acid and Co (III)-bovine carbonic anhydrase, and the rate constant is 3.6-7.2×10-1 sec-1M-1.
