title: Polymeric C-terminal cross-linked material from type-I collagen. A modified method for purification, anomalous behaviour on gel filtration, molecular weight estimation, carbohydrate content and lipid content.
abstract: Polymeric cross-linked C-terminal peptide material (poly-alpha 1CB6) from mature bovine tendon type-I collagen was prepared and purified by a modification of the method previously described [Light & Bailey (1980) Biochem. J. 185, 373-381]. Poly-alpha 1CB6 was shown to exhibit concentration-dependent aggregation effects on gel filtration due to interaction with a filtration medium. The material had an amino acid content that was very similar to a mixture of alpha 1CB6 and alpha 1CB5. The material was shown to be polydisperse with a mol.wt. range of 50 000-350 000, but chromatographic fractions were relatively homogeneous over this molecular weight range with respect to amino-acid composition. The heterogeneity of the material was not due to incomplete CNBr peptide cleavage, as poly-alpha 1CB6 did not contain detectable quantities of methionine. The material showed no discrete bands on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis but gave a constant blue stain throughout the molecular weight range described above. Lipid analysis showed that the partially purified material contained elevated levels of stearate when compared to the crude CNBr-digested starting material. This may indicate the specific association of a stearic-acid-rich lipid with the peptide material. On carbohydrate analysis poly-alpha 1CB6 was shown to contain only galactose and glucose at levels of 0.72 and 0.28% respectively. The carbohydrate and amino acid analyses indicated that (alpha 1CB6)2-(alpha 1CB5)1 may be the basic cross-linked structural unit of poly-alpha 1CB6)2-(alpha 1CB5)1 units, although the carbohydrate analysis indicated that the higher molecular weight oligomers may be enriched in alpha 1CB6.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001704:Biopolymers; D002241:Carbohydrates / Q000032:analysis; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D002850:Chromatography, Gel; D003094:Collagen; D004591:Electrophoresis, Polyacrylamide Gel; D008055:Lipids / Q000032:analysis; D008970:Molecular Weight; D010455:Peptides / Q000302:isolation & purification*
chemical_list: D000596:Amino Acids; D001704:Biopolymers; D002241:Carbohydrates; D008055:Lipids; D010455:Peptides; D003094:Collagen