"Kinetic behavior and some properties of carbonic anhydrase enzyme purified from erythrocytes of rainbow trout (Oncorhynchus mykiss) were described at +4?C. The purification procedures were composed of
hemolysate preparation, sepharose-4B-L-tyrosine-sulfanylamide affinity gel chromatography and dialyze. Yield and specific activity of enzyme were 20.9 % and 422.5 EU/mg proteins respectively. The overall purification was
approximately 200-fold. To check the purity of the enzyme, SDS olyacrylamide gel electrophoresis was performed, which showed a single band. The molecular mass of native enzyme was estimated to be 28,184 kDa by gel filtration column chromatography. Optimal pH, stable pH and optimal temperature of the enzyme were 11.5 in 0.025 M boric acid buffer, 8.5 in 0.025 M Tris-SO buffer and 25aC respectively. K and V values were 4 M max determined for p-nitrophenylacetate, as a substrate. The inhibitor effect of acetazolamide was examined. The means of activity%-[inhibitor] graph and Lineweaver-Burk graph was used in determination of I valueand K 50 i vlue nd the type of inhibition."