Proteolysis of type III collagen by collagenase and cathepsin B under high hydrostatic pressure

The effects of high hydrostatic pressures on the kinetics of hydrolysis of type III collagen from calf skin by collagenase and cathepsin B were studied. Collagen hydrolysates sampled at different time intervals (0-90 min) and at different pressures (0.1-300 MPa) were analysed by reverse-phase high pressure liquid chromatography. The rate of collagen hydrolysis decreased up to 300 MPa for both enzymes. The rate of collagen hydrolysis with cathepsin B was drastically reduced between 0.1 and 100 MPa. Significant differences in the populations of the peptides in cathepsin B hydrolysates were observed in chromatograms corresponding to different pressures. This indicated that some amino acid side-chains were less exposed to cathepsin B recognition on the surface of collagen molecules at high pressures. In contrast, the chromatograms of collagenase hydrolysates showed similar patterns, varying only by the peak heights in chromatograms corresponding to the 0.1-300 MPa pressure range. Pressureinduced decreases of the enzyme-apparent activities suggested that the activation volumes for the reaction of both enzymes were positive.