My textbook(biochemistry 4th edition, U. Satyanarayana) says that the following structure is of heparinenter image description here

and it's name should be D-Glucuronate 2-sulfate, N-sulfoglucosamine 6-sulfate. I searched on internet but could not find this kind of heparin. So could anyone give credibility that this structural compound is heparin? Atlast what is the criteria that determines whether the compound is a heparin?

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    Why downvotes? Am I wrong? – JM97 Nov 19 '16 at 12:15

This structure is exactly the same structure as found on wikipedia at the very top the page. Other variations are also shown elsewhere on that page.

Perhaps you are being misled by the presence/absence of hydrogens on the sulfate groups? The way your textbook shows it is a more physiologically relevant way as those groups would be deprotonated in normal biological conditions, but this doesn't really change the chemical structure. Heparin is normally administered as a salt.

Further, heparin is a polysaccharide chain of varying lengths (more information on that same wikipedia page) - it doesn't really make sense to say that heparin's chemical name should be "D-Glucuronate 2-sulfate, N-sulfoglucosamine 6-sulfate" - this is the name of only one disaccharide in a long, long chain. Your textbook doesn't say that either, the little "n" in the lower right corner is very important and indicates a chain of unspecified length.

  • on what basis we classify those(other variations) as heparin? – JM97 Nov 19 '16 at 2:13
  • Wikipedia shows iduronate on the very first pic while the book depicts glucuronate. – JM97 Nov 19 '16 at 2:18
  • Sorry, you are correct; if you read more on the wikipedia article it mentions the composition of heparin which includes both - it really doesn't matter much which are depicted. Heparins are just glycosaminoglycans of a variety of subunits - there is no one specific chemical called "heparin" but they all have roughly the same biological function - welcome to biology :) – Bryan Krause Nov 19 '16 at 3:09
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    This link might help you sort out some of the details in terms of where the boundaries are between heparins and similar compounds. – Bryan Krause Nov 19 '16 at 3:11

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