The effect of the subunit composition on the thermostability of collagens from the scales of freshwater fish

Collagens were isolated from the scales of carp and silver carp caught both in winter and summer. The denaturation temperatures measured by circular dichroism indicated that the thermostability of summer collagens was higher than that of the winter equivalents. The subunits of scale collagens were studied by column chromatography, which showed that the winter collagens had lower contents of α1 chain, but higher percentages of α2 and α3 chain, than the summer equivalents. It was suggested when season changes from summer to winter, the subunit compositions of scale collagens change accordingly; the content of α1 chain decreased, while contents of α2 and α3 chain increased. Therefore, the seasonal difference in the thermostability of scale collagens from the fish may be attributed to the subunit changes of collagens. This change may substantially affect tissue formation and construction, thus, have dramatic physiological consequences.