title: Purification and characterization of Taiwan cobra venom proteins with weak toxicity.
abstract: Two proteins G2a and G2b with molecular masses of approximately 24 kDa were isolated from Naja naja atra (Taiwan cobra) venom using sequential chromatography on gel filtration, ion-exchanger and reverse phase columns. The results of Edman degradation and mass analysis revealed that G2a is a cysteine-rich protein reported previously, and G2b is a novel polypeptide. CD spectra showed that the gross conformation of G2a and G2b notably differed. G2a exhibited an activity higher than that noted with G2b on inhibiting carbachol-induced muscle contraction. However, the two proteins weakly blocked muscle contraction evoked by K+. The observations that the two proteins exhibit the toxic activity in the concentration of micromolar range suggest that they are inherently weak toxins as other snake venom cysteine-rich proteins.
authors.affiliation: Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, ROC. lschang@mail.nsysu.edu.tw
authors.forename: Long-Sen
authors.initials: LS
authors.lastname: Chang
authors.forename: Jau-Cheng
authors.initials: JC
authors.lastname: Liou
authors.forename: Shinne-Ren
authors.initials: SR
authors.lastname: Lin
authors.forename: Yun-Ching
authors.initials: YC
authors.lastname: Cheng
mesh_terms: D000818:Animals; D002038:Bungarotoxins / Q000494:pharmacology; D002645:Chickens; D002942:Circular Dichroism; D004546:Elapid Venoms / Q000737:chemistry* / Q000633:toxicity*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000633:toxicity
chemical_list: D002038:Bungarotoxins; D004546:Elapid Venoms; D011506:Proteins