title: Arthropod venom citrate inhibits phospholipase A2.
abstract: 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.
authors.affiliation: Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater 74078, USA.
authors.forename: A W
authors.initials: AW
authors.lastname: Fenton
authors.forename: P R
authors.initials: PR
authors.lastname: West
authors.forename: G V
authors.initials: GV
authors.lastname: Odell
authors.forename: S M
authors.initials: SM
authors.lastname: Hudiburg
authors.forename: C L
authors.initials: CL
authors.lastname: Ownby
authors.forename: J N
authors.initials: JN
authors.lastname: Mills
authors.forename: B T
authors.initials: BT
authors.lastname: Scroggins
authors.forename: S B
authors.initials: SB
authors.lastname: Shannon
mesh_terms: 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
chemical_list: D001180:Arthropod Venoms; D002951:Citrates; D014688:Venoms; D007521:Isocitrate Dehydrogenase; D010741:Phospholipases A; D054467:Phospholipases A2; D000154:Aconitate Hydratase