Title: Apamin
CAS Registry Number: 24345-16-2
Molecular Formula: C79H131N31O24S4
Molecular Weight: 2027.34
Percent Composition: C 46.80%, H 6.51%, N 21.42%, O 18.94%, S 6.33%
Literature References: Neurotoxic polypeptide consisting of 18 amino acid residues and 2 disulfide bridges. Comprises about 2% by wt of the dried venom of Apis mellifica (mellifera), the honey bee. Isoln: E. Habermann, K. G. Reiz, Naturwissenschaften 51, 61 (1964); eidem, Biochem. Z. 341, 451 (1965). Structure: P. Haux et al., Z. Physiol. Chem. 348, 737 (1967); R. Shipolini et al., Chem. Commun. 1967, 679. Conformation: R. C. Hider, U. Ragnarsson, FEBS Lett. 111, 189 (1980); B. Busetta, ibid. 112, 138 (1980). Solution structure: J. H. B. Pease, D. E. Wemmer, Biochemistry 27, 8491 (1988). Solid-phase synthesis: J. van Rietschoten et al., Eur. J. Biochem. 56, 35 (1975); B. E. B. Sandberg, U. Ragnarsson, Int. J. Pept. Protein Res. 11, 238 (1978). Pharmacology: Wellheoner, Arch. Pharmakol. Exp. Pathol. 262, 29 (1969). Biochemistry: E. Habermann, K. G. Reiz, Biochem. Z. 343, 192 (1965). Action on CNS: E. Habermann, D. Cheng-Raude, Toxicon 13, 465 (1975). Binding and toxicity studies: C. Labbé-Jullié et al., Eur. J. Biochem. 196, 639 (1991). Review: E. Habermann, Science 177, 314-322 (1972); C. Granier, J. van Rietschoten, in Natural Toxins, D. Eaker, T. Wadström, Eds. (Pergamon, New York, 1980) pp 481-486; E. Habermann, Pharmacol. Ther. 25, 255-270 (1984).
Properties: Highly basic compd. Pharmacologic activity destroyed by oxidn with performic acid. LD50 i.v. in mice: 4 mg/kg (Habermann, Reiz); LD50 intracerebroventricularly in mice: 12 ng/animal (Labbé-Jullié).
Toxicity data: LD50 i.v. in mice: 4 mg/kg (Habermann, Reiz); LD50 intracerebroventricularly in mice: 12 ng/animal (Labbé-Jullié)
Apazone Aphidicolin Apholate Aphylline Apicycline

CAS number 24345-16-2 YesY
PubChem 16129677
ChemSpider 23975893 YesY
Jmol-3D images Image 1
Molecular formula C79H131N31O24S4
Molar mass 2027.33874 g/mol
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references
Apamin Preproprotein
Symbol Apamin
CAS number 24345-16-2
Entrez 406135
UniProt P01500

Apamin is an 18 amino acid peptide neurotoxin found in apitoxin (bee venom).[2] Dry bee venom consists for 2-3% of apamin.[3] Apamin selectively blocks SK channels, a type of Ca2+-activated K+ channel expressed in the central nervous system. Toxicity is caused by only a few amino acids, these are cysteine1, lysine4, arginine13, arginine14 and histidine18. These amino acids are involved in the binding of apamin to the Ca2+-activated K+ channel. Due to its specificity for SK channels, apamin is used as a drug in biomedical research to study the electrical properties of SK channels and their role in the afterhyperpolarizations occurring immediately following an action potential.[4]