Isolation and partial characterization of the larval midgut trypsin from the tobacco hornworm, Manduca sexta Johannson (Lepidoptera: Sphingidale)

Abstract

1. 1. Affinity chromatography using ovomucoid and p-aminobenzamidine has been used to isolate the trypsin-like digestive protease from larval midgut homogenates and midgut content of the tobacco hornworm, Manduca sexta, Johannson. 2. 2. The enzyme is anionic and has a molecular weight of 24,000 as determined by polyacrylamide gel electrophoresis. 3. 3. Studies with inhibitors suggest the presence of both serine and histidine in the active site. 4. 4. Products obtained from the digestion of glucagon demonstrate preference for lysl and arginyl peptide bonds. 5. 5. The physical and catalytic properties of the enzyme are compared with those of other serine proteases having trypsin-like specificity.