INTERACTION OF A SOYBEAN TRYPSIN-INHIBITO R (KUNITZ) WITH CYSTEINE PROTEINASES

The interaction of cysteine proteinases from the latex of papaya fruit s (Carica papaya L.) with a soybean trypsin inhibitor( Kunitz) immobil ized on polyacrylamide gel has been studied. Only one of the latex enz ymes formed a stable complex with the immobilized inhibitor in solutio ns with a low ionic strength. This complex dissociates under mild cond itions releasing the active proteinase. Analysis of physico-chemical p roperties, content of free SH-groups, N- and C-terminal amino acid seq uences allowed us to identify the enzyme interacting with the immobili zed soybean trypsin inhibitor (Kunitz) as the papaya protease Omega.