On collagens of invertebrates with special reference to Mytilus edulis

The amino acid compositions of Metridium-, Lumbricus- and Mytilus-collagens corresponded to those of the lowest vertebrates: the content of imino acids was low and that of serine and threonine high. Metridium-collagen also contained cystine and large amounts of hydroxylysine. In Lumbricus-collagen the hydroxylation of proline was almost complete and the total content of hydroxy amino acids thus exceptionally high. The solubility of collagens from the invertebrates varied in wide range. In some cases, e. g. the byssus apparatus of Mytilus, the insolubility seems to depend on the stabilizing effect of the adjacent materials which is manifested also in the unique thermal shrinking temperature of 90°. The starch-gel electrophoretic patterns were studied on soluble collagens from the following species: octopus, Loligo, Lumbricus, Diphyllobothrium, Mytilus, and Metridium. A single α-component pattern, resembling that from lamprey, was observed in all the cases.