Purification and characterization of Taiwan cobra venom proteins with weak toxicity.
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.
Chang
Long-Sen
LS
Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, ROC. lschang@mail.nsysu.edu.tw
Liou
Jau-Cheng
JC
Lin
Shinne-Ren
SR
Cheng
Yun-Ching
YC
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
D002038:Bungarotoxins; D004546:Elapid Venoms; D011506:Proteins