The Structure of the Linkage Region of Bovine Nasal Cartilage Proteoglycan After β-Elimination and Sulfite Addition

Publisher Website
Google Scholar
Abstract
A method of peptide fingerprinting was developed allowing the separation of the majority of the tryptic peptides of purified proteoglycan subunit from bovine nasal cartilage. When this preparation was reacted with 0.2 M sodium sulfite at pH 11.5, .beta.-elimination of the substituted glycosaminoglycaans and O-linked oligosaccharides and the quantitative addition of sulfite occurred in the serine and threonine residues of the linkage region. After elimination-addition studies with sodium [35S] sulfite, 6 radiolabeled linkage peptides were isolated by 2-dimensional fingerprinting. Five of these peptides were derived from a section of the protein core in which each [35S] cysteic acid residue was separated by an average of 6-10 amino acid residues. Apart from [35S] cysteic acid, the predominant amino acids in the attached peptides were glycine and glutamic acid (or glutamine), suggesting that a combination of these amino acids in the nascent protein core may be important for the initiation of glycosaminoglycan chains during proteoglycan biosynthesis.