Further biochemical and physicochemical characterization of minor disulfide-bonded (type IX) collagen, extracted from foetal calf cartilage.
Minor disulfide-bonded collagen (previously termed X1-X7 and now called type IX collagen) was isolated from foetal calf cartilage after pepsin treatment. At least three native fractions, containing, respectively, the X1X2X3, X4, and X5X6X7 chains, were separated; and from further biochemical and physicochemical experiments (differential scanning calorimetry, electrical birefringence, rotary shadowing), we propose a tentative model for their organization within a parent molecule. X1 and X2 are molecules composed of three chains of apparent Mr 62,000 and 50,000 linked by interchain disulfide bonds and containing pepsin-sensitive regions. The cleavage of at least three of these sites, present within X2, gives rise to the X3 and X5X6X7 fractions composed of molecules 80-100 nm and 40-55 nm in length, respectively. The X5X6X7 fraction is not digested by pepsin at 30 degrees C owing to its high thermal stability (certainly explained by its high hydroxyproline + proline content). This organization is in good accordance with that proposed for chicken cartilage type IX collagen; differences could only exist in the number and (or) the location of the pepsin-sensitive sites.
D000818:Animals; D002417:Cattle; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003094:Collagen / Q000378:metabolism; D003488:Cyanogen Bromide; D004220:Disulfides; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000378:metabolism; D006132:Growth Plate / Q000032:analysis* / Q000196:embryology; D006358:Hot Temperature; D008854:Microscopy, Electron; D008970:Molecular Weight; D010434:Pepsin A / Q000378:metabolism; D010446:Peptide Fragments; D011489:Protein Denaturation; D012697:Serine Endopeptidases
D004220:Disulfides; D010446:Peptide Fragments; D003094:Collagen; D010450:Endopeptidases; D012697:Serine Endopeptidases; C028344:glutamyl endopeptidase; D010434:Pepsin A; D003488:Cyanogen Bromide