Browsing Pathways

The phenylalaline biosynthesis pathways is connected with the chorismate biosynthesis pathway. Chorismate biosynthesis produce the chorismate, which further be converted to prephenate by P-protein. Combined with cofactor, H+, prephenate has been further converted to phenylpyruvic acid by P-protein with generated water and carbon dioxide. Phenylalanine transaminase catalyzes phenylpyruvic acid to phenylalaline, and also convert glutamic acid to oxoglutaric acid. Phenylalaline will be further used in phenylalaline metabolism.

Trehalose is a disaccharide made of two glucose molecules that can be used as a store of energy, as well as water retention and protection from freezing at low temperatures. In this pathway, glucose-6-phosphate from the galactose metabolism pathway combines with uridine diphosphate glucose to form alpha,alpha-trehalose 6-phosphate, as well as uridine 5’-diphosphate and a hydrogen ion as byroducts in a reaction catalyzed by alpha,alpha-trehalose-phosphate synthase [UDP-forming]. Following this, alpha,alpha-trehalose 6-phosphate is converted to alpha,alpha-trehalose following the hydrolytic cleavage of its phosphate group by trehalose-phosphate phosphatase. Alpha,alpha-trehalose can then function as energy stores until it is broken down as a part of the trehalose degradation pathway when needed.

This pathway is a compilation of Escherichia coli inner membrane transport complexes that transport compounds from the periplasmic space into the cytosol. Many compound classes are carried by these inner membrane transport complexes including sugars, amino acids, and lipids.

This pathway is a compilation of Escherichia coli inner membrane transport complexes that transport compounds from the periplasmic space into the cytosol. Many compound classes are carried by these inner membrane transport complexes including sugars, amino acids, and lipids.

Fructose metabolism begins with the transport of beta-D-glucose 6-phosphate through a glucose PTS permease. This compound is isomerized by a glucose-6-phosphate isomerase resulting in fructose 6-phosphate. This compound can be phosphorylated by two different enzymes: a pyridoxal phosphatase/fructose 1,6-bisphosphatase or an ATP-driven 6-phosphofructokinase-1, resulting in fructose 1,6-biphosphate. This compound can either react with a fructose bisphosphate aldolase class 1 resulting in D-glyceraldehyde 3-phosphate and dihydroxyacetone phosphate or through a fructose biphosphate aldolase class 2 resulting in D-glyceraldehyde 3-phosphate. This compound can then either react in a reversible triosephosphate isomerase resulting in dihydroxyacetone phosphate or react with a phosphate through an NAD-dependent glyceraldehyde 3-phosphate dehydrogenase resulting in glyceric acid 1,3-biphosphate. This compound is dephosphorylated by a phosphoglycerate kinase resulting in 3-phosphoglyceric acid. This compound, in turn, can either react with a 2,3-bisphosphoglycerate-independent phosphoglycerate mutase or a 2,3-bisphosphoglycerate-independent phosphoglycerate mutase resulting in 2-phospho-D-glyceric acid. This compound interacts with an enolase resulting in a phosphoenolpyruvic acid and water. Phosphoenolpyruvic acid can react either through an AMP-driven phosphoenoylpyruvate synthase or an ADP-driven pyruvate kinase protein complex resulting in pyruvic acid. The pyruvic acid reacts with CoA through an NAD-driven pyruvate dehydrogenase complex resulting in carbon dioxide and an acetyl-CoA which gets incorporated into the TCA cycle pathway.

Fructose metabolism begins with the transport of beta-D-glucose 6-phosphate through a glucose PTS permease. This compound is isomerized by a glucose-6-phosphate isomerase resulting in fructose 6-phosphate. This compound can be phosphorylated by two different enzymes: a pyridoxal phosphatase/fructose 1,6-bisphosphatase or an ATP-driven 6-phosphofructokinase-1, resulting in fructose 1,6-biphosphate. This compound can either react with a fructose bisphosphate aldolase class 1 resulting in D-glyceraldehyde 3-phosphate and dihydroxyacetone phosphate or through a fructose biphosphate aldolase class 2 resulting in D-glyceraldehyde 3-phosphate. This compound can then either react in a reversible triosephosphate isomerase resulting in dihydroxyacetone phosphate or react with a phosphate through an NAD-dependent glyceraldehyde 3-phosphate dehydrogenase resulting in glyceric acid 1,3-biphosphate. This compound is dephosphorylated by a phosphoglycerate kinase resulting in 3-phosphoglyceric acid. This compound, in turn, can either react with a 2,3-bisphosphoglycerate-independent phosphoglycerate mutase or a 2,3-bisphosphoglycerate-independent phosphoglycerate mutase resulting in 2-phospho-D-glyceric acid. This compound interacts with an enolase resulting in a phosphoenolpyruvic acid and water. Phosphoenolpyruvic acid can react either through an AMP-driven phosphoenoylpyruvate synthase or an ADP-driven pyruvate kinase protein complex resulting in pyruvic acid. The pyruvic acid reacts with CoA through an NAD-driven pyruvate dehydrogenase complex resulting in carbon dioxide and an acetyl-CoA which gets incorporated into the TCA cycle pathway.

L-alanine is an essential component of proteins and peptidoglycan. The latter also contains about three molecules of D-alanine for every L-alanine. Only about 10 percent of the total alanine synthesized flows into peptidoglycan.There are at least 3 ways to begin the biosynthesis of alanine. The first method for alanine biosynthesis begins with L-cysteine produced from L-cysteine biosynthesis pathway. L-cysteine reacts with an [L-cysteine desulfurase] L-cysteine persulfide through a cysteine desulfurase resulting in a release of [L-cysteine desulfurase] l-cysteine persulfide and L-alanine. The second method starts with pyruvic acid reacting with L-glutamic acid through a glutamate-pyruvate aminotransferase resulting in a oxoglutaric acid and L-alanine. The third method starts with L-glutamic acid interacting with Alpha-ketoisovaleric acid through a valine transaminase resulting in an oxoglutaric acid and L-valine. L-valine reacts with pyruvic acid through a valine-pyruvate aminotransferase resulting Alpha-ketoisovaleric acid and L-alanine. This first step of the pathway, which can be catalyzed by either of two racemases (biosynthetic or catabolic), also serves an essential role in biosynthesis because its product, D-alanine, is an essential component of cell wall peptidoglycan (murein). D-alanine is metabolized by an ATP driven D-alanine ligase A and B resulting in D-alanyl-D-alanine. This product is incorporated into the peptidoglycan biosynthesis. L-alanine is metabolized with alanine racemase, either catabolic or metabolic resulting in a D-alanine. This compound reacts with water and a quinone through a D-amino acid dehydrogenase resulting in Pyruvic acid, hydroquinone and ammonium, thus entering the central metabolism and thereby can serve as a total source of carbon and energy. The role of the dadX racemase is degradative and dadX racemase can be induced by alanine and is subject to catabolite repression.

The degradation of of adenosine nucleotides starts with AMP reacting with water through a nucleoside monophosphate phosphatase results in the release of phosphate and a adenosine. Adenosine reacts with water and hydrogen ion through an adenosine deaminase resulting in the release of ammonium and a inosine. Inosine reacts with phosphate through a inosine phosphorylase resulting in the release of an alpha-D-ribose-1-phosphate and an hypoxanthine. Hypoxanthine reacts with a water molecule and a NAD molecule through an hypoxanthine hydroxylase resulting in the release of an hydrogen ion, an NADH and a xanthine. Xanthine in turn is degraded by reacting with a water molecule and a NAD through xanthine NAD oxidoreductase resulting in the release of NADH, a hydrogen ion and urate.

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.

The reaction of pyruvate to cytochrome bd terminal oxidase electron transfer starts with 2 pyruvate and 2 water molecules reacting in a pyruvate oxidase resulting in the release of 4 electrons into the inner membrane, and releasing 2 carbon dioxide molecules , 2 acetate and 4 hydrogen ion into the cytosol. 2 ubiquinone,4 hydrogen ion and 4 electron ion react resulting in the release of 2 ubiquinol . The 2 ubiquinol in turn release 4 hydrogen ions into the periplasmic space through a cytochrome bd-I terminal oxidase and releasing 4 electrons through the enzyme. Oxygen and 4 hydrogen ion reacts with the 4 electrons resulting in 2 water molecules.