Purification and characterization of extracellular XXXX protease inhibitor, ECPI-2, from Chlorella sp.

@entity462 @entity14377 @entity467 @entity1735 @entity214
An extracellular @entity462 protease inhibitor (ECPI-2) was purified to homogeneity from the culture filtrate of Chlorella sp. 4533 by the combination of various column chromatographies. The molecular mass of the inhibitor was estimated to be 340 kDa by @entity214 -PAGE. The inhibitor was extremely heat-stable under acidic or neutral condition. ECPI-2 exhibited an inhibitory activity against the proteolytic activity of papain, ficin, or chymopapain, but not against stem bromelain or @entity467 . The inhibitor showed no inhibitory activity against trypsin, alpha-chymotrypsin or thermolysin. ECPI-2 contains 33.6% @entity1735 residues by weight and @entity14377 at a molar ratio of 1:2. The proteolysis of the inhibitor by trypsin or alpha-chymotrypsin was apparent, but the inhibitory activity of ECPI-2 was unaffected by these enzymes. The alpha-chymotrypsin hydrolysis product from ECPI-2 was further separated into six fractions by gel filtration. From these results, it is suggested that ECPI-2 has several reactive sites for papain.
