Browsing Pathways

The colonic acid building blocks biosynthesis starts with a Beta-D-Glucose undergoing a transport reaction mediated by a glucose PTS permease. The permease phosphorylates the Beta-D-Glucose, producing a Beta-D-Glucose 6-phosphate. This compound can either change to an Alpha-D-Glucose 6-phosphate spontaneously or into a fructose 6-phosphate through a glucose-6-phosphate isomerase. The latter compound can also be present in E.coli through the interaction of D-fructose and a mannose PTS permease which phosphorylate the D-fructose. Fructose 6-phosphate interacts in a reversible reaction with mannose-6-phosphate isomerase in order to produce a Alpha-D-mannose 6-phosphate. This compound can also be present in E.coli through the interaction of Alpha-D-mannose and a mannose PTS permease which phosphorylates the alpha-D-mannose. Alpha-D-mannose 6-phosphate interacts in a reversible reaction with a phosphomannomutase to produce a alpha-D-mannose 1-phosphate. This compound in turn with a hydrogen ion and gtp undergoes a reaction with a mannose-1-phosphate guanylyltransferase, releasing a pyrophosphate and producing a guanosine diphosphate mannose. Guanosine diphosphate mannose interacts with gdp-mannose 4,6-dehydratase releasing a water, and gdp-4-dehydro-6-deoxy-D-mannose. This compound in turn with hydrogen ion and NADPH interact with GDP-L-fucose synthase releasing NADP and producing a GDP-L-fucose. The Alpha-D-Glucose 6-phosphate interacts in a reversible reaction with phosphoglucomutase-1 to produce a alpha-D-glucose 1-phosphate. This in turn with UTP and hydrogen ion interact with UTP--glucose-1-phosphate uridyleltransferase releasing a pyrophosphate and UDP-glucose. UDP-glucose can either interact with galactose-1-phosphate uridylyltransferase to produce a UDP-galactose or in turn with NAD and water interact with UDP-glucose 6-dehydrogenase releasing a NADH and a hydrogen ion and producing a UDP-glucuronate. GDP-L-fucose, UDP-glucose, UDP-galactose and UDP-glucuronate are sugars that need to be activated in the form of nucleotide sugar prior to their assembly into colanic acid, also known as M antigen. Colanic acid is an extracellular polysaccharide which has been linked to a cluster of 19 genes(wca).

The biosynthesis of threonine starts with L-aspartic acid being phosphorylated by an ATP driven Aspartate kinase resulting in an a release of an ADP and an L-aspartyl-4-phosphate. This compound interacts with a hydrogen ion through an NADPH driven aspartate semialdehyde dehydrogenase resulting in the release of a phosphate, an NADP and a L-aspartate-semialdehyde.The latter compound interacts with a hydrogen ion through a NADPH driven aspartate kinase / homoserine dehydrogenase resulting in the release of an NADP and a L-homoserine. L-homoserine is phosphorylated through an ATP driven homoserine kinase resulting in the release of an ADP, a hydrogen ion and a O-phosphohomoserine. The latter compound then interacts with a water molecule threonine synthase resulting in the release of a phosphate and an L-threonine.

The metabolism of starch and sucrose begins with D-fructose interacting with a D-glucose in a reversible reaction through a maltodextrin glucosidase resulting in a water molecule and a sucrose. D-fructose is phosphorylated through an ATP driven fructokinase resulting in the release of an ADP, a hydrogen ion and a Beta-D-fructofuranose 6-phosphate. This compound can also be introduced into the cytoplasm through either a mannose PTS permease or a hexose-6-phosphate:phosphate antiporter. The Beta-D-fructofuranose 6-phosphate is isomerized through a phosphoglucose isomerase resulting in a Beta-D-glucose 6-phosphate. This compound can also be incorporated by glucose PTS permease or a hexose-6-phosphate:phosphate antiporter. The beta-D-glucose 6 phosphate can also be produced by a D-glucose being phosphorylated by an ATP-driven glucokinase resulting in a ADP, a hydrogen ion and a Beta-D-glucose 6 phosphate. The beta-D-glucose can produce alpha-D-glucose-1-phosphate by two methods: 1.-Beta-D-glucose is isomerized into an alpha-D-Glucose 6-phosphate and then interacts in a reversible reaction through a phosphoglucomutase-1 resulting in a alpha-D-glucose-1-phosphate. 2.-Beta-D-glucose interacts with a putative beta-phosphoglucomutase resulting in a Beta-D-glucose 1-phosphate. Beta-D-glucose 1-phosphate can be incorporated into the cytoplasm through a glucose PTS permease. This compound is then isomerized into a Alpha-D-glucose-1-phosphate The beta-D-glucose can cycle back into a D-fructose by first interacting with D-fructose in a reversible reaction through a Polypeptide: predicted glucosyltransferase resulting in the release of a phosphate and a sucrose. The sucrose then interacts in a reversible reaction with a water molecule through a maltodextrin glucosidase resulting in a D-glucose and a D-fructose. Alpha-D-glucose-1-phosphate can produce glycogen in by two different sets of reactions: 1.-Alpha-D-glucose-1-phosphate interacts with a hydrogen ion and an ATP through a glucose-1-phosphate adenylyltransferase resulting in a pyrophosphate and an ADP-glucose. The ADP-glucose then interacts with an amylose through a glycogen synthase resulting in the release of an ADP and an Amylose. The amylose then interacts with 1,4-α-glucan branching enzyme resulting in glycogen 2.- Alpha-D-glucose-1-phosphate interacts with amylose through a maltodextrin phosphorylase resulting in a phosphate and a glycogen. Alpha-D-glucose-1-phosphate can also interacts with UDP-galactose through a galactose-1-phosphate uridylyltransferase resulting in a galactose 1-phosphate and a Uridine diphosphate glucose. The UDP-glucose then interacts with an alpha-D-glucose 6-phosphate through a trehalose-6-phosphate synthase resulting in a uridine 5'-diphosphate, a hydrogen ion and a Trehalose 6- phosphate. The latter compound can also be incorporated into the cytoplasm through a trehalose PTS permease. Trehalose interacts with a water molecule through a trehalose-6-phosphate phosphatase resulting in the release of a phosphate and an alpha,alpha-trehalose.The alpha,alpha-trehalose can also be obtained from glycogen being metabolized through a glycogen debranching enzyme resulting in a the alpha, alpha-trehalose. This compound ca then be hydrated through a cytoplasmic trehalase resulting in the release of an alpha-D-glucose and a beta-d-glucose. Alpha-D-glucose-1-phosphate can be metabolized to produce dTDP-Beta-L-rhamnose. This happens by Alpha-D-glucose-1-phosphate reacting with a dTTP and a hydrogen ion through a dTDP-glucose pyrophosphorylase resulting in the release of a pyrophosphate and a dTDP-alpha-D-glucose. This coumpound in turn reacts with a dTDP-glucose 4,6-dehydratase resulting in the release of a water molecule and a dTDP-4-dehydro-6-deoxy-alpha-D-glucopyranose. The latter compound reacts with a dTDP-4-dehydrorhamnose 3,5-epimerase resulting in the release of a dTDP-4-dehydro-beta-L-rhamnose. This compound in turn gets metabolized by a NADPH dependent dTDP-4-dehydrorhamnose reductase resulting in a release of a NADP and a dTDP-beta-L-rhamnose Glycogen is then metabolized by reacting with a phosphate through a glycogen phosphorylase resulting in a alpha-D-glucose-1-phosphate and a dextrin. The dextrin is then hydrated through a glycogen phosphorylase-limit dextrin α-1,6-glucohydrolase resulting in the release of a debranched limit dextrin and a maltotetraose. This compound can also be incorporated into the cytoplasm through a maltose ABC transporter. The maltotetraose interacts with a phosphate through a maltodextrin phosphorylase releasing a alpha-D-glucose-1-phosphate and a maltotriose. The maltotriose can also be incorporated through a maltose ABC transporter. The maltotriose can then interact with water through a maltodextrin glucosidase resulting in a D-glucose and a D-maltose. D-maltose can also be incorporated through a maltose ABC transporter The D-maltose can then interact with a maltotriose through a amylomaltase resulting in a maltotetraose and a D-glucose. The D-glucose is then phosphorylated through an ATP driven glucokinase resulting in a hydrogen ion, an ADP and a Beta-D-glucose 6-phosphate

The metabolism of pyrimidines begins with L-glutamine interacting with water molecule and a hydrogen carbonate through an ATP driven carbamoyl phosphate synthetase resulting in a hydrogen ion, an ADP, a phosphate, an L-glutamic acid and a carbamoyl phosphate. The latter compound interacts with an L-aspartic acid through a aspartate transcarbamylase resulting in a phosphate, a hydrogen ion and a N-carbamoyl-L-aspartate. The latter compound interacts with a hydrogen ion through a dihydroorotase resulting in the release of a water molecule and a 4,5-dihydroorotic acid. This compound interacts with an ubiquinone-1 through a dihydroorotate dehydrogenase, type 2 resulting in a release of an ubiquinol-1 and an orotic acid. The orotic acid then interacts with a phosphoribosyl pyrophosphate through a orotate phosphoribosyltransferase resulting in a pyrophosphate and an orotidylic acid. The latter compound then interacts with a hydrogen ion through an orotidine-5 '-phosphate decarboxylase, resulting in an release of carbon dioxide and an Uridine 5' monophosphate. The Uridine 5' monophosphate process to get phosphorylated by an ATP driven UMP kinase resulting in the release of an ADP and an Uridine 5--diphosphate. Uridine 5-diphosphate can be metabolized in multiple ways in order to produce a Deoxyuridine triphosphate. 1.-Uridine 5-diphosphate interacts with a reduced thioredoxin through a ribonucleoside diphosphate reductase 1 resulting in the release of a water molecule and an oxidized thioredoxin and an dUDP. The dUDP is then phosphorylated by an ATP through a nucleoside diphosphate kinase resulting in the release of an ADP and a DeoxyUridine triphosphate. 2.-Uridine 5-diphosphate interacts with a reduced NrdH glutaredoxin-like protein through a Ribonucleoside-diphosphate reductase 1 resulting in a release of a water molecule, an oxidized NrdH glutaredoxin-like protein and a dUDP. The dUDP is then phosphorylated by an ATP through a nucleoside diphosphate kinase resulting in the release of an ADP and a DeoxyUridine triphosphate. 3.-Uridine 5-diphosphate is phosphorylated by an ATP-driven nucleoside diphosphate kinase resulting in an ADP and an Uridinetriphosphate. The latter compound interacts with a reduced flavodoxin through ribonucleoside-triphosphate reductase resulting in the release of an oxidized flavodoxin, a water molecule and a Deoxyuridine triphosphate 4.-Uridine 5-diphosphate is phosphorylated by an ATP-driven nucleoside diphosphate kinase resulting in an ADP and an Uridinetriphosphate The uridine triphosphate interacts with a L-glutamine and a water molecule through an ATP driven CTP synthase resulting in an ADP, a phosphate, a hydrogen ion, an L-glutamic acid and a cytidine triphosphate. The cytidine triphosphate interacts with a reduced flavodoxin through a ribonucleoside-triphosphate reductase resulting in the release of a water molecule, an oxidized flavodoxin and a dCTP. The dCTP interacts with a water molecule and a hydrogen ion through a dCTP deaminase resulting in a release of an ammonium molecule and a Deoxyuridine triphosphate. 5.-Uridine 5-diphosphate is phosphorylated by an ATP-driven nucleoside diphosphate kinase resulting in an ADP and an Uridinetriphosphate The uridine triphosphate interacts with a L-glutamine and a water molecule through an ATP driven CTP synthase resulting in an ADP, a phosphate, a hydrogen ion, an L-glutamic acid and a cytidine triphosphate. The cytidine triphosphate then interacts spontaneously with a water molecule resulting in the release of a phosphate, a hydrogen ion and a CDP. The CDP then interacts with a reduced NrdH glutaredoxin-like protein through a ribonucleoside-diphosphate reductase 2 resulting in the release of a water molecule, an oxidized NrdH glutaredoxin-like protein and a dCDP. The dCDP is then phosphorylated through an ATP driven nucleoside diphosphate kinase resulting in an ADP and a dCTP. The dCTP interacts with a water molecule and a hydrogen ion through a dCTP deaminase resulting in a release of an ammonium molecule and a Deoxyuridine triphosphate. 6.-Uridine 5-diphosphate is phosphorylated by an ATP-driven nucleoside diphosphate kinase resulting in an ADP and an Uridinetriphosphate The uridine triphosphate interacts with a L-glutamine and a water molecule through an ATP driven CTP synthase resulting in an ADP, a phosphate, a hydrogen ion, an L-glutamic acid and a cytidine triphosphate. The cytidine triphosphate then interacts spontaneously with a water molecule resulting in the release of a phosphate, a hydrogen ion and a CDP. The CDP interacts with a reduced thioredoxin through a ribonucleoside diphosphate reductase 1 resulting in a release of a water molecule, an oxidized thioredoxin and a dCDP. The dCDP is then phosphorylated through an ATP driven nucleoside diphosphate kinase resulting in an ADP and a dCTP. The dCTP interacts with a water molecule and a hydrogen ion through a dCTP deaminase resulting in a release of an ammonium molecule and a Deoxyuridine triphosphate. The deoxyuridine triphosphate then interacts with a water molecule through a nucleoside triphosphate pyrophosphohydrolase resulting in a release of a hydrogen ion, a phosphate and a dUMP. The dUMP then interacts with a methenyltetrahydrofolate through a thymidylate synthase resulting in a dihydrofolic acid and a 5-thymidylic acid. Then 5-thymidylic acid is then phosphorylated through a nucleoside diphosphate kinase resulting in the release of an ADP and thymidine 5'-triphosphate.

Histidine biosynthesis starts with a product of PRPP biosynthesis pathway, phosphoribosyl pyrophosphate which interacts with a hydrogen ion through an ATP phosphoribosyltransferase resulting in an pyrophosphate and a phosphoribosyl-ATP. The phosphoribosyl-ATP interacts with water through a phosphoribosyl-AMP cyclohydrolase / phosphoribosyl-ATP pyrophosphatase resulting in the release of pyrophosphate, hydrogen ion and a phosphoribosyl-AMP. The same enzyme proceeds to interact with phosphoribosyl-AMP and water resulting in a 1-(5'-Phosphoribosyl)-5-amino-4-imidazolecarboxamide. The product is then isomerized by a N-(5'-phospho-L-ribosyl-formimino)-5-amino-1-(5'-phosphoribosyl)-4-imidazolecarboxamide isomerase resulting in a PhosphoribosylformiminoAICAR-phosphate, which reacts with L-glutamine through an imidazole glycerol phosphate synthase resulting in a L-glutamic acid, hydrogen ion, 5-aminoimidazole-4-carboxamide and a D-erythro-imidazole-glycerol-phosphate. D-erythro-imidazole-glycerol-phosphate reacts with a imidazoleglycerol-phosphate dehydratase / histidinol-phosphatase, dehydrating the compound and resulting in a imidazole acetol-phosphate. Next, imidazole acetol-phosphate reacts with L-glutamic acid through a histidinol-phosphate aminotransferase, releasing oxoglutaric acid and L-histidinol-phosphate. The latter compound interacts with water and a imidazoleglycerol-phosphate dehydratase / histidinol-phosphatase resulting in L-histidinol and phosphate. L-histidinol interacts with a NAD-driven histidinol dehydrogenase resulting in a Histidinal. Histidinal in turn reacts with water in a NAD driven histidinal dehydrogenase resulting in L-Histidine. L-Histidine then represses ATP phosphoribosyltransferase, regulation its own biosynthesis.

The biosynthesis of shikimate starts with D-Erythrose-4-phosphate getting transformed into 3-deoxy-D-arabino-heptulosonate-7-phosphate through a phospho-2-dehydro-3-deoxyheptonate aldolase. This is followed by a 3-dehydroquinate synthase converting the 3-deoxy-D-arabino-heptulosonate-7-phosphate into a 3-dehydroquinate which in turn is conveted to 3-dehydroshikimate through a 3-dehydroquinate dehydratase. A this point 3-dehydroshikimate can be turned into Shikimic acid through 2 different reactions involving an NADPH driven Quinate/shikimate dehydrogenase or a NADPH driven shikimate dehydrogenase 2. Shikimate can also be transported through a shikimate:H+ symporter.

The biosynthesis of Valine and L-leucine from pyruvic acid starts with pyruvic acid interacting with a hydrogen ion through a acetolactate synthase / acetohydroxybutanoate synthase resulting in a release of a carbon dioxide, a (S)-2-acetolactate. The latter compound then interacts with a hydrogen ion through a NADPH-driven acetohydroxy acid isomeroreductase resulting in the release of a NADP, a (R) 2,3-dihydroxy-3-methylvalerate. The latter compound is then dehydrated by a dihydroxy acid dehydratase resulting in the release of a water molecule an 3-methyl-2-oxovaleric acid. The 3-methyl-2-oxovaleric acid can produce an L-valine by interacting with a L-glutamic acid through a Valine Transaminase resulting in the release of a Oxoglutaric acid and a L-valine. The 3-methyl-2-oxovaleric acid then interacts with an acetyl-CoA and a water molecule through a 2-isopropylmalate synthase resulting in the release of a hydrogen ion, a Coenzyme A and a 2-Isopropylmalic acid. The isopropylimalic acid is then hydrated by interacting with a isopropylmalate isomerase resulting in a 3-isopropylmalate. This compound then interacts with an NAD driven 3-isopropylmalate dehydrogenase resulting in a NADH, a hydrogen ion and a 2-isopropyl-3-oxosuccinate. The latter compound then interacts with hydrogen ion spontaneously resulting in a carbon dioxide and a ketoleucine. The ketoleucine then interacts with a L-glutamic acid through a branched-chain amino-acid aminotransferase resulting in the oxoglutaric acid and L-leucine.

The glyoxylate cycle starts with the interaction of Acetyl-Coa with a water molecule and Oxalacetic acid interact through a Citrate synthase resulting in a release of a coenzyme a and citric acid. The citric acid gets dehydrated through a citrate hydro-lyase resulting in the release of a water molecule and cis-Aconitic acid. The cis-Aconitic acid is then hydrated in an reversible reaction through an aconitate hydratase resulting in an Isocitric acid. The isocitric acid then interacts in a reversible reaction through isocitrate lyase resulting in the release of a succinic acid and a glyoxylic acid. The glyoxylic acid then reacts in a reversible reaction with an acetyl-coa, and a water molecule in a reversible reaction, resulting in a release of a coenzyme A, a hydrogen ion and an L-malic acid. The L-malic acid interacts in a reversible reaction through a NAD driven malate dehydrogenase resulting in the release of NADH, a hydrogen ion and an Oxalacetic acid.

Cardiolipin (CL) is an important component of the inner mitochondrial membrane where it constitutes about 20% of the total lipid composition. It is essential for the optimal function of numerous enzymes that are involved in mitochondrial energy metabolism (Wikipedia). Cardiolipin biosynthesis occurs mainly in the mitochondria, but there also exists an alternative synthesis route for CDP-diacylglycerol that takes place in the endoplasmic reticulum. This second route may supplement this pathway. All membrane-localized enzymes are coloured dark green in the image. First, dihydroxyacetone phosphate (or glycerone phosphate) from glycolysis is used by the cytosolic enzyme glycerol-3-phosphate dehydrogenase [NAD(+)] to synthesize sn-glycerol 3-phosphate. Second, the mitochondrial outer membrane enzyme glycerol-3-phosphate acyltransferase esterifies an acyl-group to the sn-1 position of sn-glycerol 3-phosphate to form 1-acyl-sn-glycerol 3-phosphate (lysophosphatidic acid or LPA). Third, the enzyme 1-acyl-sn-glycerol-3-phosphate acyltransferase converts LPA into phosphatidic acid (PA or 1,2-diacyl-sn-glycerol 3-phosphate) by esterifying an acyl-group to the sn-2 position of the glycerol backbone. PA is then transferred to the inner mitochondrial membrane to continue cardiolipin synthesis. Fourth, magnesium-dependent phosphatidate cytidylyltransferase catalyzes the conversion of PA into CDP-diacylglycerol. Fifth, CDP-diacylglycerol--glycerol-3-phosphate 3-phosphatidyltransferase synthesizes phosphatidylglycerophosphate (PGP). Sixth, phosphatidylglycerophosphatase and protein-tyrosine phosphatase dephosphorylates PGP to form phosphatidylglycerol (PG). Last, cardiolipin synthase catalyzes the synthesis of cardiolipin by transferring a phosphatidyl group from a second CDP-diacylglycerol to PG. It requires a divalent metal cation cofactor.

Cardiolipin (CL) is an important component of the inner mitochondrial membrane where it constitutes about 20% of the total lipid composition. It is essential for the optimal function of numerous enzymes that are involved in mitochondrial energy metabolism (Wikipedia). Cardiolipin biosynthesis occurs mainly in the mitochondria, but there also exists an alternative synthesis route for CDP-diacylglycerol that takes place in the endoplasmic reticulum. This second route may supplement this pathway. All membrane-localized enzymes are coloured dark green in the image. First, dihydroxyacetone phosphate (or glycerone phosphate) from glycolysis is used by the cytosolic enzyme glycerol-3-phosphate dehydrogenase [NAD(+)] to synthesize sn-glycerol 3-phosphate. Second, the mitochondrial outer membrane enzyme glycerol-3-phosphate acyltransferase esterifies an acyl-group to the sn-1 position of sn-glycerol 3-phosphate to form 1-acyl-sn-glycerol 3-phosphate (lysophosphatidic acid or LPA). Third, the enzyme 1-acyl-sn-glycerol-3-phosphate acyltransferase converts LPA into phosphatidic acid (PA or 1,2-diacyl-sn-glycerol 3-phosphate) by esterifying an acyl-group to the sn-2 position of the glycerol backbone. PA is then transferred to the inner mitochondrial membrane to continue cardiolipin synthesis. Fourth, magnesium-dependent phosphatidate cytidylyltransferase catalyzes the conversion of PA into CDP-diacylglycerol. Fifth, CDP-diacylglycerol--glycerol-3-phosphate 3-phosphatidyltransferase synthesizes phosphatidylglycerophosphate (PGP). Sixth, phosphatidylglycerophosphatase and protein-tyrosine phosphatase dephosphorylates PGP to form phosphatidylglycerol (PG). Last, cardiolipin synthase catalyzes the synthesis of cardiolipin by transferring a phosphatidyl group from a second CDP-diacylglycerol to PG. It requires a divalent metal cation cofactor.