Chemical nature of intestinal-type alkaline phosphatase in human kidney

Y Nishihara1, Y Hayashi, T Adachi

  • 1Department of Pharmaceutics, Gifu Pharmaceutical University, Japan.

Clinical Chemistry
|December 1, 1992
PubMed

Approximately 10% of the alkaline phosphatase activity in human kidney is derived from the intestinal-type alkaline phosphatase isoform, which can be differentiated from adult intestinal alkaline phosphatase by selective reactivity with monoclonal antibodies. The NH2-terminal sequence of the renal intestinal-type alkaline phosphatase was shown to be identical to sequences of the adult and meconial alkaline phosphatases except for the NH2-terminal valine residue, which is missing in the renal intestinal-type enzyme. Incubation of purified meconial alkaline phosphatase with kidney homogenate resulted in removal of the NH2-terminal valine residue, indicating the presence of aminopeptidases in kidney that catalyze this hydrolysis. Furthermore, the oligosaccharide chains of the renal intestinal-type alkaline phosphatase were shown to differ from those of meconial and adult intestinal alkaline phosphatases, as revealed by lectin affinity chromatography. The heterogeneity of the intestinal-type alkaline phosphatase can therefore be generated both by partial peptide bond hydrolysis and differences in glycosylation.

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