The isolation and amino acid composition of the bone collagen in pleistocene mammals

Abstract

1. 1. The bone collagens in seven different species of Pleistocene mammals (ground sloth, gopher, dire wolf, saber-tooth cat, unidentified ungulate, western camel and western horse) were analyzed for their amino acid compositions. 2. 2. Approximately 70 per cent of demineralized proteinaceous matter in compact bones and 13 per cent in spongy bones were recovered as “pure” collagen by treatment of the demineralized bone with CaCl 2 solution. A higher yield of ca. 90 per cent was obtained when the demineralized matter from compact bone was treated with neutral buffer solutions. 3. 3. With the exception of higher amounts of alanine and smaller amounts of hydroxyproline in the ground sloth and the saber-tooth cat, amino acids are present in similar amounts in the fossil collagens and in those from modern mammals, but such minor differences may be significant. 4. 4. For the extinct ground sloth and saber-tooth cat, the amino acid composition resembles that of certain lower vertebrates with larger amounts of alanine and reduced amounts of hydroxyproline. 5. 5. The amino acid composition of the collagenof the extinct western horse differs from that of the Recent horse only in having a low histidine content.