The objective of this study was to compare the biological characteristics of the venom of the snake Bungarus candidus from three different localities of Thailand (wild-caught groups) and from a captive-born group in aspects of the lethal toxicity, the enzymatic activities, and the molecular weight of protein components. All venom samples exhibited no significant differences in lethal toxicity and the enzymatic activities of phospholipase A_2, protease, phosphodiesterase and hyaluronidase. Significant differences between the wild-caught groups and the captive-born group exhibited in the activities of acetylcholinesterase, L-amino acid oxidase and phosphomonoesterase. Among the wild-caught groups, the enzymatic activities revealed significant differences in acetylcholinesterase, phosphomonoesterase and hyaluronidase. All B. candidus venom groups exhibited high lethal toxicity, high activities of phospholipase A2, acetylcholinesterase and L-amino acid oxidase, moderate activities of hyaluronidase and phosphomonoesterase and low activities of phosphodiesterase and protease. The protein components revealed variation in SDS-PAGE pattern at the molecular weight in all groups in the range of 7.1 – 41.3 kDa.

Key words: Snake venom, Bungarus candidus, biological characteristics, geographical variation, Thailand.