Browsing Pathways

Allantoin can be degraded in anaerobic conditions. The first step involves allantoin being degraded by an allantoinase resulting in an allantoate. This compound in turn is metabolized by reacting with water and 2 hydrogen ions through an allantoate amidohydrolase resulting in the release of a carbon dioxide, ammonium and an S-ureidoglycine. The latter compund is further degrades through a S-ureidoglycine aminohydrolase resulting in the release of an ammonium and an S-ureidoglycolate. S-ureidoglycolate can be metabolized into oxalurate by two different reactions. The first reactions involves a NAD driven ureidoglycolate dehydrogenase resulting in the release of a hydrogen ion , an NADH and a oxalurate. On the other hand S-ureidoglycolate can react with NADP resulting in the release of an NADPH, a hydroge ion and an oxalurate. It is hypothesized that oxalurate can interact with a phosphate and release a a carbamoyl phosphate and an oxamate. The carbamoyl phosphate can be further degraded by reacting with an ADP, and a hydrogen ion through a carbamate kinase resulting in the release of an ammonium , ATP and carbon dioxide

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 degradation of deoxycytidine starts with deoxycytidine being introduced into the cytosol through either a nupG or nupC symporter. Once inside, it can can be degrade through water,a hydrogen ion and a deoxycytidien deaminsa resultin in the release of a ammonium and a a deoxyuridine. The deoxyuridine is then degraded through a uracil phosphorylase resulting in the release of a deoxyribose 1-phosphate and a uracil. The degradation of thymidine starts with thymidine being introduced into the cytosol through either a nupG or nupC symporter. Thymidine is then degrades through a phosphorylase resulting in the release of a thymine and a deoxyribose 1-phosphate.

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 degradation of cysteine starts with L-cysteine reacting with l-cysteine desulfhydrase resulting in the release of a hydrogen sulfide, a hydrogen ion and a a 2-aminoprop-2-enoate. The latter compound in turn reacts spontaneously to form a 2-iminopropanoate. This compound in turn reacts spontaneously with water and a hydrogen ion resulting in the release of ammonium and pyruvate.

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 citrate lyase activation starts with a 3-dephospho-CoA reacting with ATP and a hydrogen ion through a triphosphoribosyl-dephospho-CoA synthase resulting in a adenine and a 2'-(5'-triphospho-alpha-D-ribosyl)-3'-dephospho-CoA. The latter compound in turn reacts with with a citrate lyase acyl-carrier protein through a apo-citrate lyase phosphoribosyl-dephospho-CoA transferase resulting in the release of a pyrophosphate and a hydrogen ion and a holo citrate lyase acyl-carrier protein.This protein complex can either react with a hydrogen ion and a acetate resulting in the release of a water and an acetyl-holo citrate lyase acyl-carrier protein. The holo acyl-carrier protein creacts with an ATP and an acetate through a citrate lyase synthase resulting in the release of an AMP, a pyrophosphate and an acetyl-holo citrate lyase acyl-ccarrier protein. The holo citrate lyase acyl-carrier protein can also interact with an S-acetyl phosphopantethiene resulting in the release of a 4-phosphopantethiene and an acetyl-holo citrate lyase acyl-carrier protein.

The citrate lyase activation starts with a 3-dephospho-CoA reacting with ATP and a hydrogen ion through a triphosphoribosyl-dephospho-CoA synthase resulting in a adenine and a 2'-(5'-triphospho-alpha-D-ribosyl)-3'-dephospho-CoA. The latter compound in turn reacts with with a citrate lyase acyl-carrier protein through a apo-citrate lyase phosphoribosyl-dephospho-CoA transferase resulting in the release of a pyrophosphate and a hydrogen ion and a holo citrate lyase acyl-carrier protein.This protein complex can either react with a hydrogen ion and a acetate resulting in the release of a water and an acetyl-holo citrate lyase acyl-carrier protein. The holo acyl-carrier protein creacts with an ATP and an acetate through a citrate lyase synthase resulting in the release of an AMP, a pyrophosphate and an acetyl-holo citrate lyase acyl-ccarrier protein. The holo citrate lyase acyl-carrier protein can also interact with an S-acetyl phosphopantethiene resulting in the release of a 4-phosphopantethiene and an acetyl-holo citrate lyase acyl-carrier protein.

2-O-α-Mannosyl-D-glycerate (MG; also named as Alpha-Mannosylglycerate) is an organic compound that will affect the osmosis in hyperthermophilic archaea and bacteria. In E.coli, 2-O-α-mannosyl-D-glycerate PTS permease (mngA) import MG into cell, and then phosphorylate MG to 2-O-(6-phospho-α-mannosyl)-D-glycerate by phosphocarrier protein HPr. 2-O-(6-phospho-α-mannosyl)-D-glycerate is converted to glyceric acid as well as mannose 6-phosphate by alpha-mannosidase mngB. Finally, glyceric acid is catalyzed to 2-Phospho-D-glyceric acid with ATP as energy source by Glycerate kinase 2. E.coli can't use MG as osmotic stress protection, but it can use MG as a carbon source.

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.