ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBiosynthesis of heparin. Hydrogen exchange at carbon 5 of the glycuronosyl residuesHarry S. Prihar, Patrick Campbell, David Sidney Feingold, Ingvar Jacobsson, John W. Jensen, Ulf Lindahl, and Lennart RodenCite this: Biochemistry 1980, 19, 3, 495–500Publication Date (Print):February 5, 1980Publication History Published online1 May 2002Published inissue 5 February 1980https://pubs.acs.org/doi/10.1021/bi00544a016https://doi.org/10.1021/bi00544a016research-articleACS PublicationsRequest reuse permissionsArticle Views56Altmetric-Citations31LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

The epimerization of D-glucuronic to L-iduronic acid residues in the course of heparin biosynthesis is accompanied by the exchange of C-5 hydrogen atom. This feature of the reaction serves as the basis for an assay of epimerase activity, in which the release of tritium into the water of the incubation medium is measured with a D-[5-3H]glucosyluronic acid-labeled precursor polysaccharide as a substrate. This chapter discusses an experiment to study the enzymatic incorporation of radioactivity from T2O into chemically modified heparin, yielding a product suitable as a substrate in the epimerase assay. In the assay, heparin from hog mucosa was purified by repeated precipitation with cetylpyridinium chloride from 1.4 M NaCl essentially. The chapter illustrates the result by a graph providing the time course of tritium incorporation into modified heparin.