Liu C S, Chen J M, Chang C H, Chen S W, Teng C M, Tsai I H
Institute of Biological Chemistry, National Taiwan University, Taipei, China.
Biochim Biophys Acta. 1991 Apr 29;1077(3):362-70. doi: 10.1016/0167-4838(91)90552-b.
Three phospholipase A2 enzymes or homologs were purified from the venom of Trimeresurus mucrosquamatus (Taiwan habu). The most abundant one was found to be a phospholipase homolog without enzyme activity, and its complete amino acid sequence was determined using oligopeptide fragments derived from digestion by endopeptidases Glu-C, Asp-N, Lys-C and alpha-chymotrypsin, and by means of gas-phase sequencing. The sequence revealed that the protein belonged to the Lys-49 family of snake venom phospholipase A2. This protein's function was characterized as edema-inducing. The Lys-49 protein has the potential to bind membrane phospholipid and Ca2+ (Kd = 1.6 x 10(-4) M) as shown by ultraviolet difference spectra; however, the catalytic site appeared to be inactive and the edematous response was independent of the protein's hydrolytic activity. Mast cells and platelets were shown to be subject to activation by the Lys-49 protein.
从台湾竹叶青蛇（Trimeresurus mucrosquamatus）的毒液中纯化出了三种磷脂酶A2酶或其同源物。发现含量最高的一种是无酶活性的磷脂酶同源物，利用由内肽酶Glu-C、Asp-N、Lys-C和α-胰凝乳蛋白酶消化产生的寡肽片段，并通过气相测序法确定了其完整的氨基酸序列。该序列显示该蛋白质属于蛇毒磷脂酶A2的Lys-49家族。该蛋白质的功能被表征为具有致水肿作用。紫外差光谱显示，Lys-49蛋白具有结合膜磷脂和Ca2+（解离常数Kd = 1.6×10⁻⁴ M）的潜力；然而，其催化位点似乎是无活性的，且水肿反应与该蛋白的水解活性无关。肥大细胞和血小板被证明会被Lys-49蛋白激活。
