PROTEINASE ECP-32 - PROPERTIES AND SPECIF ICITY

Hydrolysis of the C-peptide from recombinant human proinsulin, porcine insulin, and melittin by the E. coli actin-degrading proteinase ECP 3 2 was studied by reverse phase high performance liquid chromatography and mass spectrometry with electrospray ion source. Proteinase ECP 32 hydrolyzed only melittin at the Ala(15)-Leu(16) or Leu(16)-Ile(17) bon ds (K-M = 2.4 x 10(-6) M). The effects of pH and buffer composition on the rate of enzymatic hydrolysis were studied, The pH optimum of meli ttin hydrolysis was 7. Phosphates inhibited, whereas ATP stimulated th e hydrolysis of melittin. Melittin was suggested as a substrate for de termining the activity of proteinase ECP 32.