Localization and partial composition of the oligosaccharide units on the propeptide extensions of type I procollagen.
Type I procollagen secreted by matrix-free chick embryo tendon cells was labeled with L-[3,3'-3H] cystine and purified by DEAE-cellulose chromatography. After bacterial collagenase digestion, the NH2- and COOH-terminal propeptides were partially characterized by ion exchange chromatography and gel filtration. Similar experiments were then conducted after labeling with either D-[6-3H] glucosamine, D-[2-3H] mannose, or D-[U-14C] glucose. On the basis of these studies and subsequent carbohydrate analysis, it was concluded that the COOH-terminal peptide contained greater than 90% of the radioactive carbohydrate which consisted predominantly of glucosamine and mannose with traces of galactosamine and galactose. Only radioactive glucosamine could be detected in the NH2-terminal propeptide. Under conditions which inhibit hydroxylation of lysine and glycosylation of hydroxylysine, unhydroxylated procollagen (protocollagen) could still be labeled with [3H] glucosamine and [3H] mannose. This suggested that glycosylation of the propeptides is at least initiated at the level of the rough endoplasmic reticulum.
D000818:Animals; D002642:Chick Embryo; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005944:Glucosamine / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D008358:Mannose / Q000378:metabolism; D009844:Oligosaccharides / Q000032:analysis*; D011347:Procollagen / Q000096:biosynthesis* / Q000302:isolation & purification; D013710:Tendons / Q000196:embryology
D009844:Oligosaccharides; D011347:Procollagen; D005947:Glucose; D005944:Glucosamine; D008358:Mannose