Characterization of acid-soluble collagen from the coelomic wall of Sipunculida

The acid-soluble collagen (ASC) was extracted from the coelomic wall of Sipunculida with 0.5 m acetic acid for 72 h. Its physicochemical properties, such as molecular weight, amino acid composition, thermal stability, IR spectra and microstructures, were characterized. The collagen composed of α1, α2 and β chains, and its proline and hydroxyproline contents were lower than those of mammalian collagen, but higher than those of other fish species. Its transition (melting) temperature was at 54.50 °C. All these data showed its difference from collagens of other known vertebrates. The lyophilized Sipunculida collagen displayed a uniform and regular network ultrastructure.