Collagen from the giant acanthocephalan Macracanthorhynchus hirudinaceus

Abstract

A protein resembling collagen was isolated from the giant acanthocephalan, Macracanthorhynchus hirudinaceus, by treatment with 0.1 m NaOH, solubilization with pepsin, and precipitation with ammonium sulfate. The protein resembled other collagens in amino acid composition; glycine accounted for a third of the total, and hydroxyproline and hydroxylysine were present. The carbohydrate content (5.5%) was intermediate between that of vertebrate and invertebrate collagens. The molecular weight (329,000) was similar to collagens of vertebrates, but lower than invertebrate collagens. Transition to gelatin was marked by a distinct reduction in viscosity and specific optical rotation, with denaturation temperatures ( T m ) of 45.8 and 46.5 °, respectively. The most distinctive characteristic of Macracanthorhynchus collagen is its apparent departure from the relationship between T m and total pyrrolidine content observed for other collagens.