Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.2.2.7 (heparinase)
 1,270 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We prepared a series of oligosaccharides from porcine intestinal heparin after extensive digestion with a mixture of Flavobacterium heparinase as well as heparitinases I and II. Previously, we reported the structures of the two glycoserines derived from the carbohydrate-protein linkage region [Sugahara et al., J. Biol. Chem., 267, 1528-1533 (1992)] and three tetrasaccharides derived from the antithrombin III-binding site [Yamada et al., J. Biol. Chem., 268, 4780-4787 (1993)]. In this study, we determined the structures of 10 other tetrasaccharides and a trisaccharide by enzymatic digestion, fast atom bombardment mass spectrometry and 500-MHz 1H NMR spectroscopy. These tetrasaccharides share the common disulphated structure, delta HexA alpha 1-4GlcN(N-sulphate)alpha 1-4IdoA(2-sulphate)alpha 1-4GlcN (where HexA is hexuronic acid and IdoA is L-iduronic acid), and their structural variations are based upon the positions of additional sulphate groups. Eight among the 10 have never been isolated as discrete structures. The structure of the trisaccharide is GlcN(N-sulphate)alpha 1-4IdoA(2-sulphate) alpha 1-4GlcN(N,6-disulphate) and is derived from the non-reducing terminus of heparin chains. This structure may represent the terminus of a biosynthetically formed native heparin chain or a newly formed non-reducing terminus exposed by a tissue endo-beta-glucuronidase which may be involved in the intracellular post-synthetic fragmentation of macromolecular heparin. The 11 structures characterized in the present study and 6 additional tetrasaccharides were used to investigate the substrate specificities of heparinase, as well as heparitinases I and II. The results indicate that modification of the adjacent glucosamine on the reducing side of the disaccharide cleavage site influences the enzymatic action of the lyases, whereas the adjacent uronic acid on the non-reducing side is not recognized by these enzymes.
 ...
PMID:Structural studies on the tri- and tetrasaccharides isolated from porcine intestinal heparin and characterization of heparinase/heparitinases using them as substrates. 818 52

The major structure of the low sulfated irregular region of porcine intestinal heparin was investigated by characterizing the hexasaccharide fraction prepared by extensive digestion of the highly sulfated region with Flavobacterium heparinase and subsequent size fractionation by gel chromatography. Structures of a tetrasaccharide, a pentasaccharide, and eight hexasaccharide components in this fraction, which accounted for approximately 19% (w/w) of the starting heparin representing the major oligosaccharide fraction derived from the irregular region, were determined by chemical and enzymatic analyses as well as 1H NMR spectroscopy. Five compounds including one penta- and four hexasaccharides had hitherto unreported structures. The structure of the pentasaccharide with a glucuronic acid at the reducing terminus was assumed to be derived from the reducing terminus of a heparin glycosaminoglycan chain and may represent the reducing terminus exposed by a tissue endo-beta-glucuronidase involved in the intracellular post-synthetic fragmentation of macromolecular heparin. Eight out of the 10 isolated oligosaccharides shared the trisaccharide sequence, -4IdceA alpha 1-4GlcNAc alpha 1-4GlcA beta 1-, and its reverse sequence, -4GlcA beta 1-4GlcNAc alpha 1-4IdceA alpha 1-, was not found. The latter has not been reported to date for heparin/heparan sulfate, indicating the substrate specificity of the D-glucuronyl C-5 epimerase. Furthermore, seven hexasaccharides shared the common trisulfated hexasaccharide core sequence delta HexA(2-sulfate)alpha 1-4GlcN(N-sulfate)alpha 1-4IdceA alpha 1-4GlcNAc alpha 1-4GlcA beta 1-4GlcN(N-sulfate) which contained the above trisaccharide sequence (delta HexA, IdceA, GlcN, and GlcA represent 4-deoxy-alpha-L-threo-hex-4-enepyranosyluronic acid, L-iduronic acid, D-glucosamine, and D-glucuronic acid, respectively) and additional sulfate groups. The specificity of the heparinase used for preparation of the oligosaccharides indicates the occurrence of the common pentasulfated octasaccharide core sequence, -4GlcN(N-sulfate)alpha 1-4HexA(2-sulfate)1-4GlcN(N-sulfate) alpha 1-4IdceA alpha 1-4GlcNAc alpha 1-4GlcA beta 1-4 GlcN(N-sulfate)alpha 1-4HexA(2-sulfate)1-, where the central hexasaccharide is flanked by GlcN(N-sulfate) and HexA(2-sulfate) on the nonreducing and reducing sides, respectively. The revealed common sequence constituted a low sulfated trisaccharide representing the irregular region sandwiched by highly sulfated regions and should reflect the control mechanism of heparin biosynthesis.
 ...
PMID:A major common trisulfated hexasaccharide core sequence, hexuronic acid(2-sulfate)-glucosamine(N-sulfate)-iduronic acid-N-acetylglucosamine-glucuronic acid-glucosamine(N-sulfate), isolated from the low sulfated irregular region of porcine intestinal heparin. 944 18