The evolution of endopeptidases. XII. The proteolytic enzymes of the honeybee (Apis mellifica L.)

Abstract 1. 1. Four fractions (A–D) with endopeptidase activity have been isolated and characterized from the midgut of adult worker honey bees. 2. 2. Fraction A exhibited a strictly basic cleavage specificity when tried on the B chain of oxidized insulin, splitting exactly as bovine trypsin only the bonds Arg 22 /Gly 23 and Lys 29 /Ala 30 . Its molecular weight is 20,000. 3. 3. From the other fractions, B and C do not resemble mammalian pancreatic proteases, but fraction D shows a cleavage specificity similar to chymotrypsin. 4. 4. With the exception of fraction C all other fractions form part of the group of “serine”-proteases. 5. 5. Clear differences were visible when the occurrence of these proteases was studied in adult workers, drones and queens. 6. 6. Apis cerana and Apis mellifica show immunologically cross-reacting material with identical cleavage specificity but different electrophoretic mobility.