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The amino acid sequence and properties of an edema-inducing Lys-49 phospholipase A2 homolog from the venom of Trimeresurus mucrosquamatus

1991; Elsevier BV; Volume: 1077; Issue: 3 Linguagem: Inglês

10.1016/0167-4838(91)90552-b

1878-1454

Chen-Sheng Liu, Jinmei Chen, Chen-Hsien Chang, Shun-Wen Chen, Che‐Ming Teng, Inn‐Ho Tsai,

Cellular transport and secretion

Three phospholipase A2 enzymes or homologs were purified 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 GluC. AspN, LysC and α-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 = 1.6·10−4 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.