Ohkura N, Kitahara Y, Inoue S, Ikeda K, Hayashi K
Department of Biochemistry, Osaka University of Pharmaceutical Sciences, Takatsuki, Osaka, 569-1094, Japan.
J Biochem. 1999 Feb;125(2):375-82. doi: 10.1093/oxfordjournals.jbchem.a022297.
A phospholipase A2 (PLA2) inhibitor was purified from the blood plasma of a sea krait, Laticauda semifasciata, by sequential chromatography on Sephadex G-200, Mono Q, and Phenyl Sepharose columns. The purified inhibitor was found to be the same type as the PLA2 inhibitors, named PLIgamma, that had been purified from the blood plasma of the Thai cobra Naja naja kaouthia [Ohkura et al. (1994) Biochem. Biophys. Res. Commun. 200, 784-788] and Chinese mamushi Agkistrodon blomhoffii siniticus [Ohkura et al. (1997) Biochem. J. 325, 527-531]. Like other PLIgammas, the L. semifasciata inhibitor (LsPLIgamma) inhibited equally all of the PLA2s investigated including Elapid venom PLA2s (group I), Crotalid and Viperid venom PLA2s (group II), and honeybee PLA2 (group III). The LsPLIgamma was a 100-kDa glycoprotein composed of two distinct subunits, LsPLIgamma-A and LsPLIgamma-B, with an approximate molar ratio of 2:1. The amino acid sequences of the two subunits were determined by alignment of the peptides obtained by lysyl endopeptidase, endoproteinase Asp-N, and staphylococcal V8 protease digestions. LsPLIgamma-A and LsPLIgamma-B were composed of 182 and 181 amino acid residues, respectively; and the former subunit was a glycoprotein containing one asparagine-linked sugar chain at the position 157. The sequences of LsPLIgamma-A and LsPLIgamma-B showed 65 and 74% homology, respectively, to those of the corresponding subunits of N. naja kaouthia PLIgamma, and had two tandem patterns of cysteine residues, characteristic of the urokinase-type plasminogen activator receptor (uPAR) and members of the Ly-6 superfamily.
通过在葡聚糖凝胶G - 200、单Q柱和苯基琼脂糖柱上进行连续色谱法，从半环扁尾海蛇（Laticauda semifasciata）的血浆中纯化出一种磷脂酶A2（PLA2）抑制剂。发现纯化后的抑制剂与从泰国眼镜蛇（Naja naja kaouthia）[大仓等人（1994年）《生物化学与生物物理学研究通讯》200，784 - 788]和中国蝮蛇（Agkistrodon blomhoffii siniticus）[大仓等人（1997年）《生物化学杂志》325，527 - 531]血浆中纯化出的PLA2抑制剂PLIgamma属于同一类型。与其他PLIgamma一样，半环扁尾海蛇抑制剂（LsPLIgamma）对所有研究的PLA2具有同等抑制作用，包括眼镜蛇科毒液PLA2（第一组）、蝰蛇科和蝮蛇科毒液PLA2（第二组）以及蜜蜂PLA2（第三组）。LsPLIgamma是一种100 kDa的糖蛋白，由两个不同的亚基LsPLIgamma - A和LsPLIgamma - B组成，摩尔比约为2:1。通过对赖氨酰内肽酶、天冬氨酸内肽酶和葡萄球菌V8蛋白酶消化得到的肽段进行比对，确定了两个亚基的氨基酸序列。LsPLIgamma - A和LsPLIgamma - B分别由182个和181个氨基酸残基组成；前一个亚基是一种糖蛋白，在第157位含有一条天冬酰胺连接的糖链。LsPLIgamma - A和LsPLIgamma - B的序列分别与泰国眼镜蛇PLIgamma相应亚基的序列具有65%和74%的同源性，并且具有两种串联的半胱氨酸残基模式，这是尿激酶型纤溶酶原激活物受体（uPAR）和Ly - 6超家族成员的特征。
