By paper chromatography, the tissue homogenate of Oncomelania snails was shown to form glutamic acid at the expense of alpha-ketoglutarate plus aspartic acid, alanine or arginine respectively. The existence of alanine-glutamate, aspartate-glutamate and arginine-glutamate transaminase in Oncomelania snail was demonstrated. By using colorimetric method, the activity of aspartate-glutamate transaminase (GOT) and alanine-glutamate transaminase (GPT) of Oncomelania snail was 1.64 +/- 0.01 and 0.99 +/- 0.01 mumol/h.mg protein respectively. GOT and GPT were not inhibited by 2 ppm bromoacetamide, but the activity of GPT was suppressed (40%) by 2 ppm nicotinanilide. A combination of 0.5 ppm bromoacetamide and 0.5 ppm nicotinanilide had no synergitic molluscicidal effect.