An Active Core in a Limited Chymotryptic Digest of Bovine Parotid Hypocalcemic Substance

概要

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An active core in a limited chymotryptic digest of a bovine parotid hypocalcemic substance was purified and some properties of that core were investigated. After digestion of hypocalcemic protein (400 mg) for 2 hr with chymotrypsin (8 mg) at 37°, the mixture (20 ml) was chromatographed at 4°on a column of Sephadex G-100 (4×70 cm) and the fraction eluted at Kav 0.2 was obtained. The fraction was active on hypocalcemic activity and further rechromatographed on Sepharose 6B in 6M guanidine hydrochloride (Gdn-HCl)-0.1M Tris-HCl at pH 8.0. Major fraction on rechromatography (Kd 0.49) was purified by preparative disc electrophoresis and the purified protein (CPD-P) was active in a dose of 0.06 mg/kg (Ca lowering rate 6.5±1.1%). Molecular weight of CPD-P was 11000 by sodium dodecyl sulfate gel (20%) electrophoresis and 12500 by gel chromatography in 6M Gdn-HCl. The amino-terminal sequence of CPD-P was Lys-Leu-identical to that of native hypocalcemic protein and the carboxyl-terminal amino acid was phenylalanine. Amino acid composition of CPD-P was shown and secondary structure of CPD-P was composed of α-helix (90%) by the measurement of CD spectrum.
社団法人日本薬学会の論文
1978-09-25