Partial characterization of collagen in several bivalve molluscs

Histological distribution and biochemical properties of collagen were examined in the edible tissues of five bivalve molluscan species. Collagen fibre was mainly distributed in the muscle connective tissues (epimysium, perimysium, and endomysium) of both mantles and adductors, and in the inner connective tissue matrix of the mantles. The collagen contents of the edible tissues varied considerably; the mantles showed much higher collagen content than the adductors. Soluble collagen could be recovered from the crude collagen fraction by a pepsin digestion method and was referred to as pepsin-solubilized collagen (PSC). The PSC showed a quite distinct SDS–PAGE pattern from those of collagen fractions prior to pepsin digestion for some species, suggesting considerable effects of pepsin digestion on the structure of the triple-helical domain.