Studies on the status of arginine residues in phospholipase A2 from Naja naja atra (Taiwan cobra) snake venom

Abstract

Publisher Summary The structural features of phospholipase A 2 (PLA 2 ) showed by chemical modification to be important for enzymatic activity are histidine, aspartic acid, tryptophan, tyrosine, and lysine residues. Therefore, a study of the role of arginine residues might throw some light on the catalytic mechanism of PLA 2 enzymes. PLA 2 from N. naja atra (Taiwan cobra) snake venom is an acidic single chain polypeptide consisting of 119 amino acid residues and contains five Arg residues at the position 16, 30, 42, 94, and 117. In this chapter, the Arg residues of N. naja atra PLA 2 are selectively modified with phenylglyoxal (PG), and the modified derivatives are separated by HPLC. Based on the changes in physicochemical and biological properties after Arg modification, the possible role played by Arg residues in N. naja atra PLA 2 is discussed. Phospholipase A 2 (PLA 2 ) from N. naja atra snake venom was subjected to arginine modification with phenylglyoxal (PG), and two major derivatives were separated by HPLC. The results of amino acid analysis and sequence determination reveals that Arg-117 and Arg-16 are modified by PG. Modification of Arg-117 and Arg-16 resulted in a decrease in enzymatic activity of PLA 2 by 12.1% and 74.6%, respectively. The results indicate that Arg-16 is important for the biological activities of PLA 2 and the modification of Arg-16 might directly distort the binding ability of PLA 2 .