METHOD OF DETERMINING CARBONIC ANHYDRASE I ACTIVITY

A method for determining hydrolase activity of carbonic anhydrase I (CAI) in a sample which employs, combination of a substrate and an inhibitor. The substrate is a substrate having higher reactivity with CAI than with CAII selected from 2-hydroxy-5-nitro-α-toluenesulfonic acid sultone, a o-nitrophenyl ester, a p-nitropheylthio ester, and a -naphthyl ester or a substrate having reactivity with both CAI and CAII selected from the group consisting of a p-nitrophenyl ester and a α-naphthyl ester. The substrate having higher reactivity with CAI than with CAII is a substrate that reacts with CAI in an amount, per amount of enzyme protein, twice or more the amount of substrate reacting with CAII, under identical substrate concentrations and reaction times and that specifically binds to CAI and serves as a substrate for hydrolase activity. The inhibitor is an inhibitor inhibiting a hydrolase other than CA, a CA inhibitor inhibiting both CAI and CAII, or a CA inhibitor inhibiting CAI more potently than CAII.