Studies on the polydispersity and heterogeneity of cartilage proteoglycans. Identification of three proteoglycan structures in bovine nasal cartilage

J. J. Hopwood, H. C. Robinson

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Three chondroitin sulphate components were isolated from adult bovine nasal cartilage after treatment with alkaline NaB3H4. Average molecular weights of 13,000, 18,600 and 28,000 were obtained for chondroitin sulphate species representing 10, 52 and 38% (w/w) of the total chondroitin sulphate respectively. Each chondroitin sulphate pool has a narrow molecular weight distribution. A proteoglycan subunit preparation, isolated from one nasal cartilage by extraction and density gradient fractionation in dissociative solvents, partitioned on a CsCl density gradient according to size and composition. Variation of proteoglycan molecular weight across the gradient was directly related to the average chondroitin sulphate chain length, which in turn reflected the relative proportion of the three chondroitin sulphate pools in each proteoglycan fraction. Consideration of proteoglycan molecular parameters, compositions and behaviour on sedimentation leads to a proposal that nasal cartilage contains three distinct proteoglycan pools, each of which has a constant number of chondroitin sulphate side chains of different average molecular weight. Molecular weight distribution parameters for these proteoglycan preparations indicate that all serine residues on the protein core capable of initiating chondroitin sulphate biosynthesis are occupied and that proteoglycan polydispersity results directly from the polydispersity of the attached chondroitin sulphate component.

Original languageEnglish
Pages (from-to)581-594
Number of pages14
JournalBiochemical Journal
Issue number3
Publication statusPublished - 1 Jan 1975

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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