T 1965 (OTTO) Nα-p-Tosyl-L-arginine methyl ester hydrochloride, 98% Cas 1784-03-8 - used as an esterolytic substrate to assess trypsin-like activity in midgut extracts. T 1965 (OTTO) Nα-p-Tosyl-L-arginine methyl ester hydrochloride, 98% Cas 1784-03-8 - used as a substrate for measuring trypsin activity of pancreatin and human intestinal samples.