Arthropod venom citrate inhibits phospholipase A2.
Citrate has been identified as a major component of honey bee (Apis mellifera) venom by gas liquid chromatography-mass spectrometry. A citrate concentration of 9% was found for dried bee venom by a coupled enzyme assay, aconitase-isocitric dehydrogenase. A liquid honey bee venom would contain 140 mM citrate concentration (if the solids content were 30%). Bee venom phospholipase was inhibited at a 43% level with a citrate concentration of 20 mM and calcium ion at 3 mM with the enzyme assay. Citrate was also found in the venoms of bumble bee, Bombus fervidus, 7%; yellow jacket, Vespula maculifrons, 4%; scorpion, Centruroides sculpturatus, 8%; tarantula, Grammastola cala, 8% and brown recluse spider venom gland extract, Loxoceles reclusa, 1.5% based on dried venom solids. Citrate may serve as an endogenous inhibitor of divalent metal ion-dependent enzymes in arthropod venoms as described by Francis et al. (1992, Toxicon 30, 1239-1246). Many arthropod venoms contain calcium-dependent phospholipases. A direct effect of citrate as a venom component may be possible. The presence of citrate in venoms must be considered in research on receptors, ion channels and divalent ion-dependent toxins.
Fenton
A W
AW
Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater 74078, USA.
West
P R
PR
Odell
G V
GV
Hudiburg
S M
SM
Ownby
C L
CL
Mills
J N
JN
Scroggins
B T
BT
Shannon
S B
SB
D000154:Aconitate Hydratase / Q000037:antagonists & inhibitors; D000818:Animals; D001180:Arthropod Venoms / Q000737:chemistry / Q000494:pharmacology*; D002951:Citrates / Q000737:chemistry / Q000494:pharmacology*; D008401:Gas Chromatography-Mass Spectrometry; D007521:Isocitrate Dehydrogenase / Q000037:antagonists & inhibitors; D008116:Lizards; D013058:Mass Spectrometry; D010741:Phospholipases A / Q000037:antagonists & inhibitors*; D054467:Phospholipases A2; D014688:Venoms / Q000737:chemistry / Q000494:pharmacology
D001180:Arthropod Venoms; D002951:Citrates; D014688:Venoms; D007521:Isocitrate Dehydrogenase; D010741:Phospholipases A; D054467:Phospholipases A2; D000154:Aconitate Hydratase