Studies on fish scale collagen of Pacific saury (Cololabis saira)

We purified and characterized Type I collagen from the scales of the Pacific saury (Cololabis saira) and compared it with collagen from other organisms. Subunit composition of C. saira collagen (2α1 + α2) was similar to that of red sea bream (Pagrus major) and porcine collagen. C. saira collagen did not form a firm gel after neutralization of pH in solution. The temperature of denaturation (24–25 °C) of C. saira collagen was slightly lower than that of P. major collagen (26–27 °C). The contents of proline and hydroxyproline were lower in red sea bream and Pacific saury collagen than in porcine collagen. Circular dichroism spectra and Fourier-transformed infrared spectra showed that heat denaturation caused unfolding of the triple helices in all three collagens.

Graphical abstractWe purified Type I collagen from the scale (A; SEM image of outer side, B; inner side) of Pacific saury (Cololabis saira), and characterized it as a first report. Its subunit composition (2α1 + α2) was similar to other species (C). The C. saira collagen did not form a firm gel (D) after the fibril-formation in neutral pH (E; SEM image). The circular dichroism (CD) spectra of the collagen solution (F) showed the triple helical structure of collagen. The denaturation temperature of the C. saira collagen was approximately 24–25 °C (G).Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We purified Type I collagen from the scale of Pacific saury (Cololabis saira). ► Its subunit composition (2α1 + α2) was similar to collagens of other species. ► The Pacific saury collagen did not form a firm gel in neutral pH. ► The denaturation temperature of the Pacific saury collagen was 24–25 °C.