Kinetic Studies of Alkaline Phosphatase from the Liver of Agama agama Lizard

Abstract

Kinetic studies were carried out on alkaline phosphatase (ALP) extracted from the liver of Agama agama lizard. Incubation of ALP extract with para – nitrophenyl phosphate formed the basis for the determination of enzyme activity. Spectrophotometric method was used to assay the enzyme, and the kinetic constants: Maximum velocity (V_max) and Michaelis Menten constant (Km) were calculated. The Km and V_max values were 2.5mM and 1.538 X 10^-3 ìmol/min respectively. Inhibition studies show that the enzyme activity was competitively inhibited by 0.67mM sodium hydrogen orthophosphate (NaH₂PO₄) with inhibition constant (Ki) of 2.27mM. The optimum pH of the enzyme was 9.9 and the optimum temperature was 35^OC. The enzyme exhibited linear Arrhenius relationship with  corresponding catalytic energy of activation (E_a) of 1.44KJmol^-1. This study gives an insight of the catalytic properties of ALP extracted from the liver of Agama agama lizard.

Keywords: Alkaline phosphatase, Agama agama, para – nitrophenyl phosphate (p - NPP), Arrhenius relationship, Michaelis Menten constant.