Synergistic interaction between two linear inhibitors on a single enzyme: Vanadate and L-phenylalanine inhibition of rat liver alkaline phosphatase

Abstract

The combined effect of two linear inhibitors of rat liver alkaline phosphatase (ALP). vanadate (Van) and L-phenylalanine (L-phe) were studied using a modification of the common Yonetani-Theorell procedure proposed for studying synergistic inhibition. The modes of inhibition of ALP by Van and L-phe as analysed using the double reciprocal plots of the Michaelis-Menten equation were mixed and uncompetitive inhibition respectively. Analysis of the combined effect of the two inhibitors showed that their inhibitory effects were mutually enhanced. The mechanistic aspects and practical applications of the procedure are discussed.

Key words: alkaline phosphatase, synergistic inhibition