作者: S Ogata , Y Hayashi , N Takami , Y Ikehara
DOI: 10.1016/S0021-9258(19)81542-9
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摘要: Membrane and soluble forms of alkaline phosphatase (ALP) were selectively prepared from human placental microsomes by treatment with 1-butanol at pH 8.5 5.5, respectively. The purified membrane (mALP) (sALP) analyzed for chemical compositions. mALP was found to contain 1 mol each palmitate, stearate, glycerol/subunit ALP, which absent in sALP. Both the contained inositol 2 ethanolamine/subunit. However, none these compounds detectable another form papain, is known cleave carboxyl-terminal region. results suggest that contains diacylglycerol, removal its conversion We then [3H]ethanolamine-labeled ALP incubating choriocarcinoma cells (JEG-3) isotope. 3H-Labeled sALP mixed unlabeled treated papain. A 3H-labeled single component digests sequential chromatography through anti-ALP-IgG-Sepharose, concanavalin A-Sepharose, Bio-Gel P-6, TSK G-2000 columns. Chemical analyses revealed sample tripeptide Thr-Thr-Asp, ethanolamine, glucosamine, mannose, inositol, phosphate. Molar ratios latter five calculated be 2, 1, 3, respectively, taking Asp as mol. sequence identified positions 482-484 primary structure deduced cDNA sequence, predicts a further extension position 513, containing hydrophobic amino acid sequence. Taken together, mature molecule lacks predicted peptide attached Asp484 glycosylphospholipid, components are characterized above. glycosylphospholipid thus considered function anchor ALP.