Browsing Pathways

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.

Leucine biosynthesis involves a five-step conversion process starting with a 3-methyl-2-oxovaleric acid interacting with acetyl-CoA and a water molecule through a 2-isopropylmalate synthase resulting in Coenzyme A, hydrogen Ion and 2-isopropylmalic acid. The latter compound reacts with isopropylmalate isomerase which dehydrates the compound resulting in a Isopropylmaleate. This compound reacts with water through a isopropylmalate isomerase resulting in 3-isopropylmalate. This compound interacts with a NAD-driven D-malate / 3-isopropylmalate dehydrogenase results in 2-isopropyl-3-oxosuccinate. This compound interacts spontaneously with hydrogen resulting in the release of carbon dioxide and ketoleucine. Ketoleucine interacts in a reversible reaction with L-glutamic acid through a branched-chain amino-acid aminotransferase resulting in Oxoglutaric acid and L-leucine. 2-isopropylmalate synthase and terminal transaminase TyrB can both be suppressed by leucine. 2-keto-isovalerate and tyrosine can both inhibit the TyrB, which lead to absence of IlvE activity. Without IlvE activity, 2-ketoisocaproate could not convert to leucine since branched-chain amino-acid aminotransferase (IlvE) is the only enzyme to facilitate the reaction.

The selenium metabolism begins with the introduction of selenate and selenite to the cytosol through a sulphate permease system. Once in the cell, selenate can be reduced to selenite through nitrate reductases A and Z. Selenite then interacts with glutathione and 2 hydrogen ions resulting in the release of 2 water molecules, a hydroxide molecule, a glutathione disulfide and a selenodiglutathione. The latter compound then reacts with NADPH+H resulting in the release of a NADP, a glutathione and a glutathioselenol. Glutathiolselenol can then be oxidize resulting in a a glutathiolselenol ion which can then interact with a water molecule resulting in a release of glutathion and selenium Glutathiolselenol can also react with NADPH and hydrogen ion resulting in a release of glutathione, NADP, a hydroxide molecule and a hydrogen selenide. This compound can react in a reversible reaction by being oxidized resulting in a hydrogen selenide ion . This compound can then be phosphorylated by interacting with an ATP and releasing a AMP, a phosphate and a selenophosphate.

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.

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.

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.

The biosynthesis of ubiquinol starts the interaction of 4-hydroxybenzoic acid interacting with an octaprenyl diphosphate. The former compound comes from the chorismate interacting with a chorismate lyase resulting in the release of a pyruvic acid and a 4-hydroxybenzoic acid. On the other hand, the latter compound, octaprenyl diphosphate is the result of a farnesyl pyrophosphate interacting with an isopentenyl pyrophosphate through an octaprenyl diphosphate synthase resulting in the release of a pyrophosphate and an octaprenyl diphosphate. The 4-hydroxybenzoic acid interacts with octaprenyl diphosphate through a 4-hydroxybenzoate octaprenyltransferase resulting in the release of a pyrophosphate and a 3-octaprenyl-4-hydroxybenzoate. The latter compound then interacts with a hydrogen ion through a 3-octaprenyl-4-hydroxybenzoate carboxy-lyase resulting in the release of a carbon dioxide and a 2-octaprenylphenol. The latter compound interacts with an oxygen molecule and a hydrogen ion through a NADPH driven 2-octaprenylphenol hydroxylase resulting in a NADP, a water molecule and a 2-octaprenyl-6-hydroxyphenol. The 2-octaprenyl-6-hydroxyphenol interacts with an S-adenosylmethionine through a bifunctional 3-demethylubiquinone-8 3-O-methyltransferase and 2-octaprenyl-6-hydroxyphenol methylase resulting in the release of a hydrogen ion, an s-adenosylhomocysteine and a 2-methoxy-6-(all-trans-octaprenyl)phenol. The latter compound then interacts with an oxygen molecule and a hydrogen ion through a NADPH driven 2-octaprenyl-6-methoxyphenol hydroxylase resulting in a NADP, a water molecule and a 2-methoxy-6-all trans-octaprenyl-2-methoxy-1,4-benzoquinol. The latter compound interacts with a S-adenosylmethionine through a bifunctional 2-octaprenyl-6-methoxy-1,4-benzoquinone methylase and S-adenosylmethionine:2-DMK methyltransferase resulting in a s-adenosylhomocysteine, a hydrogen ion and a 6-methoxy-3-methyl-2-all-trans-octaprenyl-1,4-benzoquinol. The 6-methoxy-3-methyl-2-all-trans-octaprenyl-1,4-benzoquinol. interacts with a reduced acceptor, an oxygen molecule through a 2-octaprenyl-3-methyl-6-methoxy-1,4-benzoquinone hydroxylase resulting in the release of a water molecule, an oxidized electron acceptor and a 3-demethylubiquinol-8. The latter compound then interacts with a S-adenosylmethionine through a bifunctional 3-demethylubiquinone-8 3-O-methyltransferase and 2-octaprenyl-6-hydroxyphenol methylase resulting in a hydrogen ion, a S-adenosylhomocysteine and a ubiquinol 8.

The process of flavin biosynthesis starts with GTP being metabolized by interacting with 3 molecules of water through a GTP cyclohydrolase resulting in a release of formic acid, a pyrophosphate, two hydrog ions and 2,5-diamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one or 2,5-Diamino-6-hydroxy-4-(5-phosphoribosylamino)pyrimidine. Either of these compounds interacts with a water molecule and a hydrogen ion through a fused diaminohydroxyphosphoribosylaminopyrimidine deaminase / 5-amino-6-(5-phosphoribosylamino)uracil reductase resulting in an ammonium and 5-amino-6-(5-phospho-D-ribosylamino)uracil. This compound then interacts with a hydrogen ion through a NADPH dependent fused diaminohydroxyphosphoribosylaminopyrimidine deaminase / 5-amino-6-(5-phosphoribosylamino)uracil reductase resulting in the release of a NADP and a 5-amino-6-(5-phospho-D-ribitylamino)uracil. This compound then interacts with a water molecule through a 5-amino-6-(5-phospho-D-ribitylamino)uracil phosphatase resulting in a release of a phosphate, and a 5-amino-6-(D-ribitylamino)uracil. D-ribulose 5-phosphate interacts with a3,4-dihydroxy-2-butanone 4-phosphate synthase resulting in the release of formic acid, a hydrogen ion and 1-deoxy-L-glycero-tetrulose 4-phosphate. A 5-amino-6-(D-ribitylamino)uracil and 1-deoxy-L-glycero-tetrulose 4-phosphate interact through a 6,7-dimethyl-8-ribityllumazine synthase resulting in the release of 2 water molecules, a phosphate, a hydrogen ion and a 6,7-dimethyl-8-(1-D-ribityl)lumazine. The latter compound then interacts with a hydrogen ion through a riboflavin synthase resulting in the release of a riboflavin and a 5-amino-6-(d-ribitylamino)uracil. The riboflavin is then phosphorylated through an ATP dependent riboflavin kinase resulting in the release of a ADP, a hydrogen ion and a FLAVIN MONONUCLEOTIDE. The flavin mononucleotide interad with a hydrogen ion and an ATP through the riboflavin kinase resulting in the release of a pyrophosphate and Flavin Adenine dinucleotide. This compound is then exported into the periplasm through a FMN/FAD exporter.