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Calciseptine
Molecular weight	7036

Contents 1 Calciseptine 2 Sequence 3 Isolation 4 Target 5 References

[edit] Calciseptine

Calciseptine (CaS) is a natural neurotoxin isolated from the black mamba Dendroaspis p. polyepsis venom. This toxin consists of 60 amino acids with four disulfide bonds. Calciseptine specifically blocks L-Type calcium channels, but not other voltage-dependent Ca²⁺ channels such as N-type and T-type channels.<ref name="De Weille1991"> De Weille, J. R., Schweitz, H., Maes, P., Tartar, A. & Lazdunski, M. Proc. Natl. Acad. Sci. USA 88, 1991 2437-2440.</ref>

[edit] Sequence

Its amino acid sequence is: RICYI HKASL PRATK TCVEN TCYKM FIRTQ REYIS REGCG CPTAM WPYQT ECCKG DRCNK

[edit] Isolation

Calciseptine is purified from the venom of black mamba Dendroaspis p. polyepsis via three isolation steps: (1) gel filtration, (2) ion exchange on TSK SP 5PW, and (3) reverse-phase chromatograghy on RP18. It represents 2.8% of the total venom components. <ref name="Schweitz1990"> Schweitz, H., Bidard, J.-N. & Lazdunski, M. Toxicon 1990, 18, 847-856.</ref>

[edit] Target

Calciseptine blocks L-type Ca²⁺ channels.<ref name="De Weille1991"> De Weille, J. R., Schweitz, H., Maes, P., Tartar, A. & Lazdunski, M. Proc. Natl. Acad. Sci. USA 88, 1991 2437-2440.</ref> As a result, it blocks spontaneous contractions of rat portal vein, contractions of the rat thoracic aorta, uterus and cardiac preparations.

[edit] References

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