BIOSYNTHESIS OF CHONDROITIN SULFATE - MICROSOMAL ACCEPTORS OF SULFATE, GLUCURONIC ACID, AND N-ACETYLGALACTOSAMINE
BIOSYNTHESIS OF CHONDROITIN SULFATE - MICROSOMAL ACCEPTORS OF SULFATE, GLUCURONIC ACID, AND N-ACETYLGALACTOSAMINE
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DOI:
10.1021/bi00744a017
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发表时间:
1973-01-01
期刊:
影响因子:
2.9
通讯作者:
SILBERT, JE
中科院分区:
文献类型:
--
作者:
RICHMOND, ME;DELUCA, S;SILBERT, JE
Martha E. Richmond, Silvana DeLuca,% and Jeremiah E. Silbert* abstract: A microsomal preparation from chick embryo epiphyseal cartilage has previously been shown to accept [35S] sulfate,[14C] glucuronic acid, and/V-[^ acetylgalactos-amine into endogenous glycosaminoglycan. The endogenous glycosaminoglycan has now been characterized further. Incu-bations of microsomalpreparations at pH 6.5 with 3'-phos-phoadenosine 5'-phosphosulfate resulted in incorporation of sulfate into endogenous chondroitin 6-sulfate (60-70%) and chondroitin 4-sulfate (30-40%) while incubations at pH 7.8 resulted inincorporation into chondroitin 6-sulfate ex-clusively. Incorporation appeared to be into occasional non-sulfated galactosamine units in predominantly sulfated c^ Considerable information is now available on the inter-mediates involved in thesynthesis of the heteropolysaccharide (glycosaminoglycan) portion of the proteoglycan, chondroitin sulfate. Uridine sugar nucleotides have been shown to be the precursors for the sugars of the chondroitin chains (Silbert, 1964; Perlman et al., 1964) and significant sulfation of newly synthesized chondroitin (Silbert and DeLuca, 1969) has been demonstrated with 3'-phosphoadenosine 5'-phosphosulfate as sulfate donor. It is also well established that at least some of the chondroitin sulfate heteropolysaccharide found in extra-cellular matrix is linked toserine units of protein by an alkali-labile xylosyl-serine bond which is part of a glucuronosylgalactosyl-galactosyl-xylosyl-serine protein-polysaccharide “bridge”(Rodén and Smith, 1966; Lindahl and Rodén, 1966; Helting and Rodén, 1968). Uridine sugar nucleotides have been shown to be intermediates in the synthesis of this “bridge”(Helting and Rodén, 1969a, b; Brandt et al., 1969; Baker et al., 1972). Alternatively, it has been suggested that some of the polysaccharide chains may be attached to protein by an as yet unidentified bond which is alkali stable (Katsura and Davidson, 1966; Lyons and Singer, 1971). This could t From the Connective Tissue Research Laboratory, Boston Veterans Administration Hospital, and the Departments of Medicine and of Biochemistry and Pharmacology, Tufts University School of Medicine, Boston, Massachusetts 02130. Received March 6, 1973. This investiga-tion was supported in part by Research Grant AM-08816 from the National Institute of Arthritis and Metabolic Diseases, National Insti-tutes of Health. A preliminary report has been published (Richmond eta!., 1971). t Present address: American National Red Cross, Blood Research Laboratory, Bethesda, Md. 20014.