title: Isolation, toxicity and amino terminal sequences of three major neurotoxins in the venom of Malayan krait (Bungarus candidus) from Thailand.
abstract: We isolated the most lethal toxins in the venom of the Malayan krait (Bungarus candidus), one of the medically most important snake species in southeast Asia. Three beta-BTx like basic neurotoxins, T1-1, T1-2, and T2, with PLA2 activity were isolated from pooled venom of eight B. candidus from southern Thailand by cation-exchange chromatography, followed by adsorption chromatography on hydroxylapatite and RP-HPLC, with 14-, 16-, and 4-fold increases in toxicity compared to crude venom. The LDs50 determined in mice weighing 18-20 g were 0.26, 0.22, and 0.84 micro g per mouse with i.v. injection. T1-1 and T1-2 possessed comparable lethal toxicities to those of beta1-BTx, the most toxic neurotoxin in B. multicinctus venom, and the major neurotoxin in B. flaviceps venom. The apparent molecular weights of the native toxins were approximately 25-25.5 kDa. They consist of two polypeptide chains with apparent molecular weights of 15.5-16.5 and 8-8.5 kDa, respectively. The amino terminal sequences of the two chains of each of the toxins determined by Edman degradation exhibited considerable similarity with those of the A-chains and B-chains of beta-BTxs in the venom of Bungarus multicinctus.
authors.affiliation: Queen Saovabha Memorial Institute, The Thai Red Cross Society, 1871 Rama IV Rd, Bangkok 10330, Thailand.
authors.forename: Orawan
authors.initials: O
authors.lastname: Khow
authors.forename: Lawan
authors.initials: L
authors.lastname: Chanhome
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Omori-Satoh
authors.forename: Yuko
authors.initials: Y
authors.lastname: Ogawa
authors.forename: Ryohei
authors.initials: R
authors.lastname: Yanoshita
authors.forename: Yuji
authors.initials: Y
authors.lastname: Samejima
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kuch
authors.forename: Dietrich
authors.initials: D
authors.lastname: Mebs
authors.forename: Visith
authors.initials: V
authors.lastname: Sitprija
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017838:Bungarus / Q000235:genetics; D004546:Elapid Venoms / Q000201:enzymology / Q000302:isolation & purification* / Q000633:toxicity*; D005260:Female; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009498:Neurotoxins / Q000235:genetics / Q000302:isolation & purification* / Q000633:toxicity*; D010446:Peptide Fragments / Q000302:isolation & purification* / Q000633:toxicity*; D010741:Phospholipases A / Q000378:metabolism; D054467:Phospholipases A2; D013785:Thailand
chemical_list: D004546:Elapid Venoms; D009498:Neurotoxins; D010446:Peptide Fragments; D010741:Phospholipases A; D054467:Phospholipases A2