Metal Displacement Effects on Monoesterase Activity of Calf Intestinal Alkaline Phosphatase

dc.contributor.authorIgunnu, Adedoyin
dc.contributor.authorArise, R. O.
dc.contributor.authorAdebayo, J. O.
dc.contributor.authorMalomo, S. O.
dc.description.abstractThe mechanism of modulation of alkaline phosphatase activity by metal ions has not been fully elucidated. We investigated the time-dependent modulatory effects of Mg 2+ and Zn 2+ in promoting the hydrolysis of para-nitrophenyl phosphate (monoesterase reaction) by calf intestinal alkaline phosphatase (CIAP) and the effects of addition of the activating metal ions to the metal-inhibited enzyme. The CIAP was affected by changes in pre-incubation time in the presence of the two metal cofactors. Both Mg 2+ (0.1 – 0.25 mM) and Zn 2+ (0.1 – 5 mM) modulated Zn 2+ - and Mg 2+ - inhibited monoesterase activity of CIAP. The CIAP activity was inhibited when the enzyme was pre-incubated with 1 mM Ca 2+ . Further addition of Mg 2+ (0.1 – 2 mM) did not completely restore the activity though partly relieved the inhibition caused by Ca 2+ - pre-incubated enzyme. Again, addition of 2mM Zn 2+ to Ca 2+ - pre-incubated alkaline phosphatase completely restored the activity of the enzyme. This study suggests that Mg 2+ and Zn 2+ regulate the catalytic property of each other and modulate the inhibitory effect of Ca 2+ in alkaline phosphatase catalysis through a displacement effect. The modulation of Ca 2+ -inhibited CIAP activity by Mg 2+ and Zn 2+ may be explored in the treatment of disorders of bone mineralization especially those arising from inhibited alkaline phosphatase activity.en_US
dc.description.sponsorshipSelf Sponsoreden_US
dc.publisherNigerian Society of Biochemistry and Molecular Biologyen_US
dc.relation.ispartofseriesNigerian Journal of Biochemistry and Molecular Biology;Vol. 27, Issue 1
dc.subjectAlkaline phosphataseen_US
dc.subjectmonoesterase reactionen_US
dc.subjectmetal ion cofactorsen_US
dc.subjectdisplacement reactionen_US
dc.titleMetal Displacement Effects on Monoesterase Activity of Calf Intestinal Alkaline Phosphataseen_US


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