Browsing Pathways

Sedoheptulose bisphospate bypass pathway demonstrates a series of reaction that form D-Erythrose 4-phosphate for pentose phosphate pathway and glycerone phosphate for glycolysis and pyruvate dehydrogenase pathway. D-Sedoheptulose 7-phosphate is obtained from pentose phosphate pathway, which later converted to sedoheptulose 1,7-bisphosphate via 6-phosphofructokinase-1. Fructose-bisphosphate aldolase class 2 catalyzes sedoheptulose 1,7-bisphosphate to form D-Erythrose 4-phosphate and pyruvate dehydrogenase.

Fructosamines are compounds that result from glycation reactions between a sugar and a primary amine, followed by isomerization via the Amadori rearrangement. In fructoselysine degradation, fructoselysine firstly converts to 1-[(5-Amino-5-carboxypentyl)amino]-1-deoxyfructose by protein frlC, and then 1-[(5-Amino-5-carboxypentyl)amino]-1-deoxyfructose is transformed to fructoselysine-6-phosphate by fructoselysine kinase which is powered by ATP. Fructoselysine-6-phosphate finally degrades to β-D-Glucose 6-phosphate and L-lysine by fructoselysine 6-phosphate deglycase.

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.

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.

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.

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.

GTP, produced in the nucleotide de novo biosyntheis pathway, interacts with a water molecule through a GTP cyclohydrolase resulting in a formate, hydrogen ion and a 7,8-dihydroneopterin 3'-triphosphate. The latter compound interacts with a water molecule through a dihydroneopterin triphosphate pyrophosphohydrolase resulting in the release of a pyrophosphate, a hydrogen ion and a 7,8-dihydroneopterin 3'-phosphate. The latter compound interacts with water spontaneously resulting in the release of a phosphate and a 7,8 dihydroneopterin. The latter compound interacts with a dihydroneopterin aldolase resulting in the release of a glycolaldehyde and a 6-hydroxymethyl-7,8-dihydropterin. This compound then is then diphosphorylated by reacting with a ATP driven 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase resulting in the release of a hydrogen ion, an AMP and 6-hydroxymethyl-7,8-dihydropterin diphosphate. GTP interacts with a cyclic pyranopterin monophosphate synthase resulting in the release of a diphosphate and a cyclic pyranopterin phosphate. The latter compound interacts with a thiocarboxylated small subunit of molybdopterin synthase (a protein) and a water molecule through a molybdopterin synthase resulting in the release of 4 hydrogen ions, 2 small subunits of molybdopterin synthase and a molybdopterin. The molybdopterin interacts with an ATP and a hydrogen ion through a molybdopterin adenylyltransferase resulting in the release of a diphosphate and a molybdopterin adenine dinucleotide. The latter compound is then metabolized by a hydrogen ion and a molybdate through a molybdopterin molybdenumtransferase resulting in the release of an AMP, a water molecule and a molybdopterin cofactor. The molybdopterin cofactor can procede to the guanylyl molybdenum cofactor biosynthesis pathway or it can be metabolized into a cytidylyl molybdenum cofactor by interacting with a CTP and a hydrogen ion through a molybdenym cofactor cytidylyltransferase resulting in the release of a pyrophosphate and a cytidyllyl molybdenum 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.