Kinetic Studies of Alkaline Phosphatase Extracted from Rabbit (Lepus townsendii) Liver
Studies were carried out to ascertain some kinetic properties of alkaline phosphatase (ALP) extracted from Lepus townsendii liver. Incubation of ALP extract with 4-nitrophenylphosphate (4-NPP) in glycine-NaOH buffer mixture at 37°C for 30 min formed the basis for determination of enzyme activity. Spectrophotometric method was used to assay for the enzyme activity for 30 min and the kinetic constants-maximum enzyme velocity (Vmax) and Michealis-Menten constant (Km) were evaluated. The Km and Vmax values were 0.5x10-3 M and 20x10-6 M min-1, respectively. Inhibition studies showed that ALP activity was competitively inhibited by 0.67 mM sodium hydrogen orthophosphate (NaH2PO4) and the inhibition constant (Ki) was 0.9x10-3 M. The optimum pH value for ALP activity was about 9.2 and optimum temperature registered 45°C. ALP activity exhibited linear Arrhenius relationship at temperature greater than 44.95°C with corresponding catalytic energy of activation (Ea) = 15.23 KJ mole-1. The present study gave insights into characteristic catalytic properties of ALP extracted from L. townsendii liver.
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