TY - JOUR
AU - LEE,, Chen-Yuan
AB - Abstract The two most basic β-bungarotoxins (β3- and β4-toxins) and another, less neurotoxic β-bungarotoxin (β5-toxin) were purified from Bungarus multicinctus venom, by a combination of CM-Sephadex C-25 column chromatography and Sephadex G-75 gel filtration. The three toxins consisted of two dissimilar polypeptides (A chain, 120 amino acid residues; B chain, 60 residues). The LD50 values of the β3- and β4- toxins were 0.066 μg and 0.072 μ/g of mouse, respectively, and their phospholipase A activities were 43.2 and 36.5 units/mg of toxin, respectively. β5-Toxin was weaker in neurotoxicity (LD50, 0.13 μ/mg of mouse) than the others, and its phospholipase activity was 47.6 units/mg of toxin. Each toxin was separated into RCM-A and RCM-B chains after reduction and S-carboxymethylation. The RCM-polypeptides were maleylated and digested with TPCK-trypsin. The tryptic peptides were sequenced with manual Edman degradation or the dansyl-Edman method. The final alignment of the tryptic peptides from the respective RCM-polypeptides was deduced on the basis of the amino acid sequences of the A and B chains of β1-bungarotoxin (β1-toxin). The amino acid sequences of the A chains of the β3- and β4-toxins were identical but differed from those of the A chains of the β1- and β2-toxins by 4 amino acid substitutions in the COOH-terminal portions (residues 109-120) and substitution at position 87. The amino acid sequences of the B chains of the β3- and β4-toxins differed from each other, but they were identical with those of the B chains of the β1- and β2-toxins, respectively. The amino acid sequence of the A chain of β5-toxin differed from that of the A chain of β1-toxin by consecutive substitutions in residues 55–60 and substitutions at positions 23, 87, and 89. The amino acid sequence of the B chain of β5-toxin was identical with those of the B chains of β1- and β3-toxin. This content is only available as a PDF. Author notes 1Present address, Department of Medical Chemistry, Osaka Medical College, Takatsuki, Osaka 569. 2Deceased February 21, 1981. © 1982, by the Japanese Biochemical Society
TI - Amino Acid Sequences of Three β-Bungarotoxins (β3-, β4-, and β5-Bungarotoxins) from Bungarus multicinctus Venom. Amino Acid Substitutions in the A Chains
JF - The Journal of Biochemistry
DO - 10.1093/oxfordjournals.jbchem.a133844
DA - 1982-04-01
UR - https://www.deepdyve.com/lp/oxford-university-press/amino-acid-sequences-of-three-bungarotoxins-3-4-and-5-bungarotoxins-0jK8XxREsV
SP - 1531
EP - 1548
VL - 91
IS - 5
DP - DeepDyve
ER -