Nishihara Y, Hayashi Y, Adachi T, Koyama I, Stigbrand T, Hirano K
Department of Pharmaceutics, Gifu Pharmaceutical University, Japan.
Clin Chem. 1992 Dec;38(12):2539-42.
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.
人肾中约10%的碱性磷酸酶活性来自肠型碱性磷酸酶同工型，它可通过与单克隆抗体的选择性反应与成人肠碱性磷酸酶区分开来。肾肠型碱性磷酸酶的NH2末端序列显示与成人及胎粪碱性磷酸酶的序列相同，只是肾肠型酶中缺少NH2末端缬氨酸残基。将纯化的胎粪碱性磷酸酶与肾匀浆一起温育导致NH2末端缬氨酸残基去除，表明肾中存在催化这种水解作用的氨肽酶。此外，凝集素亲和色谱显示肾肠型碱性磷酸酶的寡糖链与胎粪及成人肠碱性磷酸酶的寡糖链不同。因此，肠型碱性磷酸酶的异质性可由部分肽键水解和糖基化差异产生。
