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Two-step inactivation of bee venom phospholipase A2 by scalaradial

Two-step inactivation of bee venom phospholipase A2 by scalaradial

Authors :
Robert S. Jacobs
M. S. de Carvalho
Source :
Biochemical Pharmacology. 42:1621-1626
Publication Year :
1991
Publisher :
Elsevier BV, 1991.

Abstract

Scalaradial (SLD), a marine natural product isolated from the sponge (Cacospongia sp., possesses anti-inflammatory properties in vivo and in vitro (Pharmacologist 32: 168, 1990). In this study we characterize its effects against bee venom phospholipase A2 (PLA2; EC 3.1.1.4). SLD is a potent inactivator of bee venom PLA2 with an IC50 value of 0.07 microM. Inactivation of bee venom PLA2 occurred in a time-dependent, irreversible manner. The rate of inactivation followed first-order reaction kinetics and was dependent on the concentration of SLD. Kinetic analysis suggested a two-step mechanism of inactivation: an initial apparent noncovalent binding (Ki = 4.5 x 10(-5) M) followed by covalent modification. The rate of inactivation was reduced markedly in the presence of excess phosphatidylcholine, suggesting that modification of the enzyme occurs at or near the substrate binding site.

Details

ISSN :
00062952
Volume :
42
Database :
OpenAIRE
Journal :
Biochemical Pharmacology
Accession number :
edsair.doi.dedup.....cc2d366181be66081a9db3da4752b79c
Full Text :
https://doi.org/10.1016/0006-2952(91)90432-5