|Phenylalanine racemase (ATP-hydrolysing)|
|PDB structures||RCSB PDB PDBe PDBsum|
The enzyme phenylalanine racemase (EC 18.104.22.168, phenylalanine racemase, phenylalanine racemase (adenosine triphosphate-hydrolysing), gramicidin S synthetase I) is the enzyme that acts on amino acids and derivatives. It activates both the L & D stereo isomers of phenylalanine to form L-phenylalanyl adenylate and D-phenylalanyl adenylate, which are bound to the enzyme. These bound compounds are then transferred to the thiol group of the enzyme followed by conversion of its configuration, the D-isomer being the more favorable configuration of the two, with a 7 to 3 ratio between the two isomers. The racemisation reaction of phenylalanine is coupled with the highly favorable hydrolysis of adenosine triphosphate (ATP) to adenosine monophosphate (AMP) and pyrophosphate (PP), thermodynamically allowing it to proceed. This reaction is then drawn forward by further hydrolyzing PP to inorganic phosphate (Pi), via Le Chatelier's principle.
Problems in the digestion of phenylalanine (phe) to tyrosine (tyr) lead to the buildup of both phe and phenylpyruvate, in a disease called Phenylketonuria (PKU). These two compounds build up in the blood stream and cerebral spinal fluid, which can lead to mental retardation if left untreated. Treatment consists of a restricted diet of foods that contain phe or compounds that can breakdown into phe. Children in the US are routinely tested for this at birth. For more information see the Phenylketonuria page or the link below.
Compound C00079 at KEGG Pathway Database.Compound C00002 at KEGG Pathway Database.Enzyme 22.214.171.124 at KEGG Pathway Database.Compound C00020 at KEGG Pathway Database.Compound C00013 at KEGG Pathway Database.Compound C00001 at KEGG Pathway Database.Reaction R00686 at KEGG Pathway Database.Pathway MAP00360 at KEGG Pathway Database.Compound C00018 at KEGG Pathway Database. |}
Adenosine triphosphate (ATP) is an organic compound and hydrotrope that provides energy to drive many processes in living cells, such as muscle contraction, nerve impulse propagation, condensate dissolution, and chemical synthesis. Found in all known forms of life, ATP is often referred to as the "molecular unit of currency" of intracellular energy transfer. When consumed in metabolic processes, it converts either to adenosine diphosphate (ADP) or to adenosine monophosphate (AMP). Other processes regenerate ATP so that the human body recycles its own body weight equivalent in ATP each day. It is also a precursor to DNA and RNA, and is used as a coenzyme.
Adenosine diphosphate (ADP), also known as adenosine pyrophosphate (APP), is an important organic compound in metabolism and is essential to the flow of energy in living cells. ADP consists of three important structural components: a sugar backbone attached to adenine and two phosphate groups bonded to the 5 carbon atom of ribose. The diphosphate group of ADP is attached to the 5’ carbon of the sugar backbone, while the adenine attaches to the 1’ carbon.
Glucose 6-phosphate is a glucose sugar phosphorylated at the hydroxy group on carbon 6. This dianion is very common in cells as the majority of glucose entering a cell will become phosphorylated in this way.
A salvage pathway is a pathway in which a biological product is produced from intermediates in the degradative pathway of its own or a similar substance. The term often refers to nucleotide salvage in particular, in which nucleotides are synthesized from intermediates in their degradative pathway.
Glyceraldehyde 3-phosphate, also known as triose phosphate or 3-phosphoglyceraldehyde and abbreviated as G3P, GA3P, GADP, GAP, TP, GALP or PGAL, is the metabolite that occurs as an intermediate in several central pathways of all organisms. With the chemical formula H(O)CCH(OH)CH2OPO32-, this anion is a monophosphate ester of glyceraldehyde.
Dihydroxyacetone phosphate (DHAP, also glycerone phosphate in older texts) is the anion with the formula HOCH2C(O)CH2OPO32-. This anion is involved in many metabolic pathways, including the Calvin cycle in plants and glycolysis. It is the phosphate ester of dihydroxyacetone.
Inosinic acid or inosine monophosphate (IMP) is a nucleotide. Widely used as a flavor enhancer, it is typically obtained from chicken byproducts or other meat industry waste. Inosinic acid is important in metabolism. It is the ribonucleotide of hypoxanthine and the first nucleotide formed during the synthesis of purine nucleotides. It can also be formed by the deamination of adenosine monophosphate by AMP deaminase. It can be hydrolysed to inosine.
Gramicidin S or Gramicidin Soviet is an antibiotic that is effective against some gram-positive and gram-negative bacteria as well as some fungi.
Phosphoenolpyruvate is the ester derived from the enol of pyruvate and phosphate. It exists as an anion. PEP is an important intermediate in biochemistry. It has the highest-energy phosphate bond found in organisms, and is involved in glycolysis and gluconeogenesis. In plants, it is also involved in the biosynthesis of various aromatic compounds, and in carbon fixation; in bacteria, it is also used as the source of energy for the phosphotransferase system.
3-Phosphoglyceric acid (3PG, 3-PGA, or PGA) is the conjugate acid of 3-phosphoglycerate or glycerate 3-phosphate (GP or G3P). This glycerate is a biochemically significant metabolic intermediate in both glycolysis and the Calvin-Benson cycle. The anion is often termed as PGA when referring to the Calvin-Benson cycle. In the Calvin-Benson cycle, 3-phosphoglycerate is typically the product of the spontaneous scission of an unstable 6-carbon intermediate formed upon CO2 fixation. Thus, two equivalents of 3-phosphoglycerate are produced for each molecule of CO2 that is fixed. In glycolysis, 3-phosphoglycerate is an intermediate following the dephosphorylation (reduction) of 1,3-bisphosphoglycerate.
Tyrocidine is a mixture of cyclic decapeptides produced by the bacteria Bacillus brevis found in soil. It can be composed of 4 different amino acid sequences, giving tyrocidine A–D. Tyrocidine is the major constituent of tyrothricin, which also contains gramicidin. Tyrocidine was the first commercially available antibiotic, but has been found to be toxic toward human blood and reproductive cells. The function of tyrocidine within its host B. brevis is thought to be regulation of sporulation.
Fructose 1,6-bisphosphate, also known as Harden-Young ester, is fructose sugar phosphorylated on carbons 1 and 6. The β-D-form of this compound is common in cells. Upon entering the cell, most glucose and fructose is converted to fructose 1,6-bisphosphate.
Fructose 6-phosphate is a derivative of fructose, which has been phosphorylated at the 6-hydroxy group. It is one of several possible fructosephosphates. The β-D-form of this compound is very common in cells. The great majority of glucose is converted to fructose 6-phosphate upon entering a cell. Fructose is predominantly converted to fructose 1-phosphate by fructokinase following cellular import.
The long chain fatty acyl-CoA ligase is an enzyme of the ligase family that activates the oxidation of complex fatty acids. Long chain fatty acyl-CoA synthetase catalyzes the formation of fatty acyl-CoA by a two-step process proceeding through an adenylated intermediate. The enzyme catalyzes the following reaction,
Purine metabolism refers to the metabolic pathways to synthesize and break down purines that are present in many organisms.
Ribose-phosphate diphosphokinase is an enzyme that converts ribose 5-phosphate into phosphoribosyl pyrophosphate (PRPP). It is classified under EC 126.96.36.199.
In enzymology, a phosphoribosylanthranilate isomerase [ PRAI ] is an enzyme that catalyzes the third step of the synthesis of the amino acid tryptophan.
Phenylalanine ammonia lyase is an enzyme that catalyzes a reaction converting L-phenylalanine to ammonia and trans-cinnamic acid. Phenylalanine ammonia lyase (PAL) is the first and committed step in the phenyl propanoid pathway and is therefore involved in the biosynthesis of the polyphenol compounds such as flavonoids, phenylpropanoids, and lignin in plants. Phenylalanine ammonia lyase is found widely in plants, as well as some bacteria, yeast, and fungi, with isoenzymes existing within many different species. It has a molecular mass in the range of 270–330 kDa. The activity of PAL is induced dramatically in response to various stimuli such as tissue wounding, pathogenic attack, light, low temperatures, and hormones. PAL has recently been studied for possible therapeutic benefits in humans afflicted with phenylketonuria. It has also been used in the generation of L-phenylalanine as precursor of the sweetener aspartame.
In enzymology, a phenylalanine-tRNA ligase is an enzyme that catalyzes the chemical reaction
Phenylalanyl-tRNA synthetase, mitochondrial (FARS2) is an enzyme that in humans is encoded by the FARS2 gene. This protein encoded by FARS2 localizes to the mitochondrion and plays a role in mitochondrial protein translation. Mutations in this gene have been associated with combined oxidative phosphorylation deficiency 14, also known as Alpers encephalopathy, as well as spastic paraplegia 77 and infantile-onset epilepsy and cytochrome c oxidase deficiency.