Calciseptine

Calciseptine (CaS) is a natural neurotoxin isolated from the black mamba Dendroaspis p. polylepis 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.^[1]

Additional recommended knowledge

Recognize and detect the effects of electrostatic charges on your balance

Essential Laboratory Skills Guide

What is the Correct Way to Check Repeatability in Balances?

Sequence

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

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. ^[2]

Target

Calciseptine blocks L-type Ca²⁺ channels.^[1] As a result, it blocks spontaneous contractions of rat portal vein, contractions of the rat thoracic aorta, uterus and cardiac preparations.

References

1. ^ ^{a b} De Weille, J. R., Schweitz, H., Maes, P., Tartar, A. & Lazdunski, M. Proc. Natl. Acad. Sci. USA 88, 1991 2437-2440.
2. ^ Schweitz, H., Bidard, J.-N. & Lazdunski, M. Toxicon 1990, 18, 847-856.