Citation

Nakamura S, Nakai M, Nakashima K, Ogawa T, Shimohigashi Y, Ohno M, Kihara H, Yamane T, Ashida T. J. Mol. Recognit. 1996; 9(1): 23-30.

Affiliation

Department of Chemistry, Faculty of Science, Kyushu University, Fukuoka, Japan.

Copyright

(Copyright © 1996, John Wiley and Sons)

DOI

10.1002/(SICI)1099-1352(199601)9:1<23::AID-JMR235>3.0.CO;2-P

PMID

8723316

Abstract

Trimeresurus flavoviridis (Habu snake) venom aspartate-49-phospholipase A2 (Asp-49-PLA2) was reacted at pH 9.0 with a 2-fold molar excess of 2,4,6-trinitrobenzenesulfonate in the absence of Ca2+ and two trinitrophenylated derivatives were isolated by HPLC. One was a derivative modified at Lys-11 and its activity was mostly retained. The other was a derivative modified at both Lys-11 and Lys-72 and its activity was 40% that of unmodified enzyme. Trinitrophenylation of Lys-72 appeared to bring about a conformational disorder at the lipid-water interface recognition site and thus a reduction of activity. When the enzyme was modified in the presence of Ca2+, activity decreased at a rate much faster than that in the absence of Ca2+ and Lys-69 came to be modified. These results suggested that conformational displacement of Asp-49-PLA2 of a local to global type occurs upon the binding of Ca2+. The derivative modified at Lys-69 had 28% activity and existed as a monomer. This supports a previous assumption that Lys-69 participates in dimerization of group II Asp-49-PLA2s Brunie et al. (1985) J. Biol. Chem. 260, 9742-9749 and shows that dimerization is not necessarily essential for activity manifestation.

Language: en