KINETICS OF INHIBITION OF ALKALINE-PHOSPHATASE FROM GREEN CRAB (SCYLLA-SERRATA) BY N-BROMOSNCCINIMIDE

The inactivation of alkaline phosphatase from green crab (Scylla serra ta) by N-bromosuccinimide has been studied using the kinetic method of the substrate reaction during modification of enzyme activity previou sly described by Tsou [(1988), Adv. Enzymol. Related Areas Mol. Biol. 61, 381-436]. The results show that inactivation of the enzyme is a sl ow, reversible reaction. The microscopic rate constants for the reacti on of the inactivator with free enzyme and the enzyme-substrate comple x were determined. Comparison of these rate constants indicates that t he presence of substrate offers marked protection of this enzyme again st inactivation by N-bromosuccinimide. The above results suggest that the tryptophan residue is essential for activity and is situated at th e active site of the enzyme.