Heparins

Heparin - Guidance notes

Heparin is a highly-sulphated glycosaminoglycan found mainly in mast cell granules; it’s principal clinical use is as an anticoagulant but its reactivity with many effector proteins is leading to potential applications in a variety of human diseases. Heparin is chemically-related to heparan sulphate (HS), a common component of cell surfaces that plays key roles in the control of cell growth and development. Heparin, and oligosaccharides derived from heparin, can be used as functional analogues of the sulphated regions of HS but with the proviso that the high charge density of heparin may, in some instances, lack the discrimination of protein binding seen in the less sulphated HS. To some degree this limitation can be overcome by use of size-limited heparin saccharides and by the preparation of specifically-desulphated heparin derivatives, all available from Iduron and listed below; such key reagents can give valuable information on the structural elements necessary for the activity under study. If more in depth work is needed then data acquired using our heparin-based reagents can guide the selection of heparin and HS motifs in our extensive “HepMer” range of defined oligomeric sequences.

Page, C. (2013 Heparin and Related Drugs: beyond Antocoagulant Activity. ISRN Pharmacology, 2013; ID 910973

Cassinelli, G. and Naggi, A. (2016) Old and new applications of Non-Antocoagulant Heparin. Int. Cardiol. 21251: S14-S21

Kjellen, L. and Lindahl, U. (2018) Specificity of glycosaminoglycan-protein interactions. Current Opinion in Structural Biology 50:101–108

Gallagher J. (2015) Fell-Muir Lecture: Heparan Sulphate and the art of cell regulation: a polymer chain conducts the protein orchestra. Int J Exp Pathol. 96:203-231.

Product info:

Heparin and Low Molecular Weight Heparin

Heparin (cat # HEP001) has an average molecular weight of about 15 kDa it is highly polydisperse with a considerable spread of mol wts.

LMW Heparin is made via partial digestion of heparin with heparinase I, it is less polydisperse than the heparin it is made from (HEP001) with a molecular weight range of 1800 – 7500 daltons.

The profiles below a comparison between the partially digested LMW Heparin and the parent Heparin. The arrows show elution positions of a  heparin hexasaccharide dp6 (mol wt 1800) and a heparin dp24 (mol wt 7200) main peak in heparin polymer (23 mins) corresponds to a mol wt of approx 14Kda

Heparin Polymer Molecular Weight (Mw) Series prepared from High Grade Unfractionated Heparin (UF)

These highly-purified, low polydispersity heparins were isolated from our High-Grade Heparin (Cat. No. HEP-HG 001; Mw 15,700) and cover the range of polymer chains present in unfractionated heparins.

Molecular weights were determined using the USP Heparin Sodium molecular weight calibrant for molecular weight measurement of unfractionated heparin. 

Selectively Desulphated Heparin Polymers

Prepared by site-selective, chemical methods to desulphate heparin at the aminosulphate (N-sulfate), C2 of uronic acid, C6 of glucosamine; in N-desulphated, re N-Acetylated heparin the “free” amino group has been acetylated. These products are useful for investigating the influence of specific sulphate groups on the conformation and binding properties of heparin.  

Heparin Oligosaccharides

Prepared by controlled partial depolymerisation of UF heparin by Heparinase I and separation of the derived oligosaccharides using high resolution gel filtration. The products cover the entire range of oligosaccharides present in Low Molecular Weight Heparins. 

General formula: *UA,2S – (GlcNS,6S – IdoA,2S) – GlcNS,6S

*the uronic acid at the non-reducing end of the chain contains a C4-C5 double bond due to the endolytic action of Heparinase I

Although the main disaccharide in heparin is the trisulphated unit GlcNS,6S – IdoA,2S heparin also contains di-, mono- and non-sulphated units; thus each size class of oligosaccharide, though substantially homogeneous in molecular size, contains structures that vary in content and pattern of sulphation. The 2mg amounts of supplied material can be subfractionated (eg. by SAX-hplc) for further analysis of naturally-occurring heparin sequences within a specific size class or classes. 

dp = degree of polymerisation where ‘n’ is the number of monosaccharides. So a dp4 (HO04) is a tetrasaccharide, a dp6 (HO06) is a hexasaccharide, a dp8 (HO08)is a octasaccharide………etc.

Main Heparin Disaccharide Unit

*the uronic acid at the non-reducing end of the chain contains a C4-C5 double bond due to the endolytic action of Heparinase I

Selectively Desulphated Heparin Oligosaccharides

Heparin oligosaccharides made by partial digestion of high quality heparin modified by standard chemical methods to selectively remove the sulphate groups.

Investigate the specific protein binding motifs in Heparin and HS GAGs. Use these products in conjunction with our heparin oligosaccharides and HepMers to investigate the essential functional groups and specific oligosaccharide chain length required for high affinity/optimal protein interactions.

4 variations of selectively desulphated heparin oligosaccharides are available, dp4 – dp12:

2-O-desulphated heparin oligosaccharides Sulphate group removed from the C2 of iduronate

6-O-desulphated heparin oligosaccharides Sulphate group removed from the C6 of glucosamine

N-desulphated heparin oligosaccharides Sulphate group removed from the N sulphate of the glucoasmine

N-desulphated re N-acetylated heparin oligosaccharides The free amino group (NH+3) in N-desulphated heparin has been modified by acetylation