Analysis and improvement of stability of pepsin-solubilized collagen from skin of carp (Cyprinus carpio)

Pepsin is widely used for the extraction of pepsin-solubilized collagens (PSC) from many resources. PSC-A and PSC-P were prepared from carp skin using 0.1 mol L-1 acetic acid and 0.02 mol L-1 Na2HPO4 (pH 7.2) as the dialysis solution, respectively. SDS-PAGE patterns showed PSC-A and PSC-P as type I collagens, as well as acid soluble collagen (ASC). When incubated at 40A degrees C, no degradation was observed for ASC, but PSC-A and PSC-P were degraded into short peptides, showing lower stability than ASC. The results indicate that pepsin remaining in the PSCs resulted in their degradation, which was confirmed by the inhibition using pepstatin. This research revealed the behavior of the remaining pepsin in pepsin-solubilized collagens and an approach to the PSC stability improvement was proposed. Chromatography profiles showed that new PSC prepared by the improved method had almost the same stability as ASC.