Partial characterization of collagen in mantle and adductor of pearl oyster (Pinctada fucata)

Histochemical observation clarified the presence of collagen in the connective tissues of epimysium, perimysium, and endomysium in the mantle and adductor of the pearl oyster Pinctada fucata. A small amount of soluble collagen could be obtained from the mantle and adductor by extracting a crude connective tissue fraction with 4 M guanidine hydrochloride (G/HCl) solution, without protease digestion of telopeptides. The G/HCl-soluble collagen showed two alpha bands (α1 and α2) on SDS–PAGE. The relative staining intensities of the α1 to α2 chains were decreased gradually by pepsin digestion with concomitant development of lower molecular weight components. These results suggest the existence of pepsin-sensitive regions in the triple helical domain of the α1 chain.