pattern of vanadate Inhibition of the monoesterase activity of calf intestinal alkaline phosphatase
Year: 2014
Type: article
Abstract: The mechanism of modulation of vanadate inhibition of alkaline phosphatase activity by catalytic cofactors has not been fully characterized.We investigated the effect of the interaction of catalytic cofactors (Mg 2+ and Zn 2+ ) and vanadate (an active site inhibitor) on the rate of hydrolysis of para-nitrophenyl phosphate (pNPP) (monoesterase reaction) by calf intestinal alkaline phosphatase (CIAP).The results showed that vanadate significantly inhibited ʻcofactor-freeʼ CIAP, and the inhibition was relieved by the presence of the catalytic cofactors in the reaction.Our results show that the absence of the cofactors did not significantly alter the K m of the reaction, but caused a decrease in the V max .Kinetic analyses showed that vanadate inhibited CIAP-catalyzed hydrolysis of pNPP by decreasing the V max and increasing the K m of the reaction.The presence of cofactors in the reaction alleviated the effect of vanadate by increasing the V max and decreasing the K m .The activity of the dialyzed CIAP was increased by the addition of catalytic cofactors to vanadate-inhibited enzyme.This study provides preliminary data that reversible inhibition of CIAP is subject to the influence of catalytic cofactors.Further studies will reveal detailed mechanistic aspects of this observation and its significance in the biological system.
Language: English
Subfield: Inorganic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2341563636