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

• Published in: Biochimica et biophysica acta Vol. 1077; no. 3; pp. 362 - 370
• Main Authors: Liu, C S, Chen, J M, Chang, C H, Chen, S W, Teng, C M, Tsai, I H
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 29.04.1991
• Subjects: Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Crotalid Venoms - analysis; Edema - chemically induced; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; Hydrolases; Molecular Sequence Data; Phospholipases A - analysis; Phospholipases A - isolation & purification; Phospholipases A - toxicity; Phospholipases A2; Phospholipids - metabolism; Rats; Rats, Inbred Strains; Edema; Purification; Enzyme; Induction; Phospholipase A; Biological activity; Ophidia; Vertebrata; Platelet; Enzymatic activity; Analog; Venom; Reptilia; Mast cell; Aminoacid sequence
• ISSN: 0167-4838; 0006-3002; 1879-2588
• 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.