Amino sugar and nucleotide sugar metabolism

Curator(s): Peter D'Adamo

Glycosaminoglycans (GAGs) or mucopolysaccharides are long unbranched polysaccharides consisting of a repeating disaccharide unit. Members of the glycosaminoglycan family vary in the type of hexosamine, hexose or hexuronic acid unit they contain (e.g. glucuronic acid, iduronic acid, galactose, galactosamine, glucosamine). In this pathway the fates of three types of amino sugars (neuraminate, mannosamine and glucosamines) are depicted. The central hub metabolite to this pathway is UDP-N-acetyl-D-glucosamine. This molecule can either serve as a precursor to polymeric mucopolysaccharides, a precursor to other types of amino sugars, or a precursor to fructose 6-phosphate, which can be used in fructose/mannose metabolism. In nucleotide sugar metabolism a group of biochemicals known as nucleotide sugars act as donors for sugar residues in the glycosylation reactions that produce polysaccharides.[1] They are substrates for glycosyltransferases. The nucleotide sugars are also intermediates in nucleotide sugar interconversions that produce some of the activated sugars needed for glycosylation reactions. Since most glycosylation takes place in the endoplasmic reticulum and golgi apparatus, there are a large family of nucleotide sugar transporters that allow nucleotide sugars to move from the cytoplasm, where they are produced, into the organelles where they are consumed.    
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Amino sugar and nucleotide sugar metabolism cluster_EXTRACELLULAR EXTRACELLULAR node1 node8 MurNAc-6P node1->node8 node20 GlcN-6P node1->node20 node21 GlcNAc-6P node1->node21 node105 Glc-6P node1->node105 node137 Man-6P node1->node137 node144 Fuc-1P node1->node144 node100 Glc (Ext) node1->node100 node37 GlcN (Ext) node1->node37 node9 GlcNAc (Ext) node1->node9 node143 L-fucose (ext) node1->node143 node136 Mannose (ext) node1->node136 node2 GlcNAc node2->GlcNAc node3 node3->GlcNAc node3->node21 node4 node4->GlcNAc node5 Chitobiose node5->Chitobiose node5->GlcNAc node6 3 Chitin Chitin->node5 Chitin->node6 Chitin node11 Chitin->node11 node7 2 Chitobiose->node4 Chitobiose->node7 Chitobiose node10 37 GlcNAc->node3 GlcNAc->node10 GlcNAc Chitosan node11->Chitosan node12 Chitosan->node12 node13 D-Glucosaminide node12->node13 node14 node13->node14 GlcN node14->GlcN node15 GlcN->node15 node15->GlcNAc node16 node16->GlcNAc node16->GlcN node17 3 node18 node18->GlcN node18->node17 node18->node20 node66 Fru-6P node18->node66 Glucose node18->Glucose node18->node105 node18->node137 Mannose node18->Mannose node19 node19->GlcN node19->node20 node23 node20->node23 node29 node20->node29 node22 node22->node20 node22->node21 node23->node21 node24 node24->node8 node24->node21 node25 node25->node21 node26 GlcNAc-1P node25->node26 node27 node26->node27 node31 UDP -Glc -NAc node27->node31 node28 node28->node26 node30 D-GlcN -1P node29->node30 node32 node31->node32 node35 node31->node35 node54 node31->node54 node59 node31->node59 node60 node31->node60 Lipopolysaccharide biosynthesis node31->Lipopolysaccharide biosynthesis node32->Chitin node33 node33->node21 node34 ManNAc-6P node34->node33 ManNAc node36 ManNAc->node36 node39 ManNAc->node39 node35->ManNAc node52 UDP-ManNAc node35->node52 node36->node34 node38 node38->node34 node40 Neu5Ac-9P node38->node40 node41 node40->node41 Neu5Ac node41->Neu5Ac node42 23 Neu5Ac->node42 Neu5Ac node46 Neu5Ac->node46 node43 node43->Neu5Ac node44 CMP-Neu5Ac node43->node44 NeuNGc node43->NeuNGc node51 CMP-NeuNGc node43->node51 GlcA node43->GlcA node45 node45->Neu5Ac node49 Cyt b5 (ox) node45->node49 node45->NeuNGc node45->node51 node46->ManNAc node47 3.2.1 Glycosidases node47->ManNAc node47->node52 node48 Cyt b5 (red) node48->node45 node50 node49->node50 node50->node48 wecC node52->wecC node53 UDP-ManNAcA wecC->node53 node57 UDP-GalNAcA wecC->node57 node55 UDP-GlcNAcA node54->node55 node56 tviC 5.1.-.- node55->node56 node56->node57 node58 UDP-GalNAc node58->wecC node59->node58 node61 UDP -GlcAc -eno-pyruvate node60->node61 node62 node61->node62 node63 UDP-MurAc node62->node63 Peptidoglycan synthesis node63->Peptidoglycan synthesis node64 D-Gln and D -Glu Metabolism node63->node64 Fructose Fructose->node18 node65 Fructose->node65 Fructose and mannose metabolism Fructose and mannose metabolism->Fructose Fructose and mannose metabolism->Mannose node142 L-fucose Fructose and mannose metabolism->node142 node65->node66 node67 node66->node67 node69 Glycolysis / Gluconeogenesis node66->node69 node67->node20 node68 node68->node20 node68->node66 node69->node66 node69->Glucose node69->node100 Pentose and glucuronate interconversions node70 L-Ara Pentose and glucuronate interconversions->node70 Pentose and glucuronate interconversions->GlcA GalA Pentose and glucuronate interconversions->GalA node71 node70->node71 node72 L-Ara -1P node71->node72 node73 node72->node73 node74 UDP -L -Ara node73->node74 Arabinan node74->Arabinan node75 Arabinan->node75 node75->node70 node76 D-Xyl -1P node77 node76->node77 node79 UDP -D -Xyl node77->node79 node78 node78->node74 node78->node79 node80 node79->node80 node81 1-4 -beta-D -Xylan node80->node81 node82 node81->node82 node83 D-Xylose node82->node83 node84 node85 GlcA-1P node84->node85 node86 node86->node85 node87 UDP-GlcA node86->node87 AXS node87->AXS node88 node87->node88 node90 node87->node90 node92 node87->node92 AXS->node79 node89 UDP -D -Api AXS->node89 node88->node79 node91 UDP -L -IdoA node90->node91 node93 UDP -L -Ara4O node92->node93 node94 node93->node94 node95 UDP -L -Ara4N node94->node95 node96 node95->node96 node97 UDP -L -Ara4FN node96->node97 node98 node97->node98 node99 Undecaprenyl phosphate -a -L-Ara4FN node98->node99 node101 17 Glucose->node1 Glucose->node101 Glucose node102 2 node103 node103->Glucose node103->node102 node103->node105 node104 node104->Glucose node104->node105 node106 node106->node66 node106->node105 node107 node107->node105 node109 Glc-1P node107->node109 node108 node108->node105 node108->node109 Polyketide sugar unit biosynthesis node109->Polyketide sugar unit biosynthesis node110 node110->node109 node111 UDP-Glc node110->node111 Ascorbate and aldarate metabolism node111->Ascorbate and aldarate metabolism node112 node111->node112 node113 node111->node113 node123 node111->node123 node112->node87 node114 UDP -4keto -6deoxy-D -Glc node113->node114 node115 5.1.3.- node114->node115 node116 UDP -4 -keto-Rha node115->node116 node117 1.1.1.- node116->node117 node118 UDP-Rha node117->node118 node119 node119->node109 node119->node111 node120 Gal-1P node119->node120 node121 UDP-Gal node119->node121 node122 node122->node111 node122->node121 node124 UDP-SQ node123->node124 node125 node125->node120 node125->node121 node126 node126->node120 node127 alpha-Gal node126->node127 Galactose metabolism Galactose metabolism->node127 node128 node128->GalA node129 GalA-1P node128->node129 node130 2.7.7.- node130->node129 node131 UDP-GalA node130->node131 node135 node131->node135 Starch and sucrose metabolism node131->Starch and sucrose metabolism node132 1.1.1.+ node132->node121 node132->node131 node133 node133->node74 node133->node131 node134 node134->node87 node134->node131 Pectin node135->Pectin node138 44 Mannose->node138 Mannose node139 node139->node137 node139->Mannose node140 node140->node66 node140->node137 node141 13 node142->node141 L-fucose node145 node145->node142 node145->node144 node146 node146->node137 node147 Man-1P node146->node147 node170 CDP-Glc Starch and sucrose metabolism->node170 node148 node148->node147 node150 GDP-Man node148->node150 node149 node149->node147 node149->node150 node151 node150->node151 node154 node150->node154 node152 GDP -L -Gul node151->node152 node153 GDP -L -Gal node151->node153 node152->Ascorbate and aldarate metabolism node153->Ascorbate and aldarate metabolism node155 GDP -D -ManA node154->node155 node155->Fructose and mannose metabolism node156 node156->node150 node157 GDP -4oxy -6-deoxy Man node156->node157 node159 node157->node159 node160 node157->node160 node158 node158->node157 node161 GDP -D -Rha node158->node161 node159->node161 node162 GDP -6 -deoxy-D -Tal node160->node162 node163 node163->node157 node164 GDP-Fuc node163->node164 node165 node165->node144 node165->node164 node166 node166->node109 node167 GDP-Glc node166->node167 node167->Starch and sucrose metabolism node168 node168->node109 node168->node170 node169 node169->node109 node169->node109 node175 ADP-Glc node169->node175 node171 node170->node171 node172 CDP -4 -keto-6 -deoxy-D -Glc node171->node172 node173 node172->node173 node174 CDP -4 -keto-3,6,deoxy -D-Glu node173->node174 Rfbj node174->Rfbj AscE node174->AscE RfbS node174->RfbS node175->Starch and sucrose metabolism node181 CDP-abequose Rfbj->node181 node177 CDP -4 -dehydro-3,6, /ndideoxy -D-Glc -epimer AscE->node177 node176 CDP-paratose RfbS->node176 AscF node177->AscF node179 CDP-ascarylose AscF->node179 node178 node178->node176 node180 CDP-tyv node178->node180 MurNAc MurNAc->node1 print "