|
1-pyrroline-5-carboxylic Acid
1-Pyrroline-5-carboxylic acid (systematic name 3,4-dihydro-2H-pyrrole-2-carboxylic acid) is a cyclic imino acid. Its conjugate base and anion is 1-pyrroline-5-carboxylate (P5C). In solution, P5C is in spontaneous equilibrium with glutamate-5-semialdhyde (GSA). The stereoisomer (''S'')-1-pyrroline-5-carboxylate (also referred to as L-P5C) is an intermediate metabolite in the biosynthesis and degradation of proline and arginine. In prokaryotic proline biosynthesis, GSA is synthesized from γ-glutamyl phosphate by the enzyme γ-glutamyl phosphate reductase. In most eukaryotes, GSA is synthesised from the amino acid glutamate by the bifunctional enzyme 1-pyrroline-5-carboxylate synthase (P5CS). The human P5CS is encoded by the ''ALDH18A1'' gene. The enzyme pyrroline-5-carboxylate reductase converts P5C into proline In proline degradation, the enzyme proline dehydrogenase produces P5C from proline, and the enzyme 1-pyrroline-5-carboxylate dehydrogenase converts GSA to glutamate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imino Acid
In organic chemistry, an imino acid is any molecule that contains both imine (>C=NH) and carboxyl (-C(=O)-OH) functional groups. Imino acids are structurally related to amino acids, which have amino group instead of imine—a difference of single vs double-bond between nitrogen and carbon. The simplest example is dehydroglycine. D-Amino acid oxidase is an enzyme that is able to convert amino acids into imino acids. Also the direct biosynthetic precursor to the amino acid proline is the imino acid (''S'')-Δ1-pyrroline-5-carboxylate (P5C). Related terminology Secondary amino acids, amino acids containing a secondary amine group are sometimes named imino acids, though this usage is obsolescent. The only proteinogenic amino acid of this type is proline, although the related non-proteinogenic amino acids hydroxyproline and pipecolic acid Pipecolic acid (piperidine-2-carboxylic acid) is an organic compound with the formula HNC5H9CO2H. It is a carboxylic acid derivativ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-oxo Acid
In organic chemistry, keto acids or ketoacids (also called oxo acids or oxoacids) are organic compounds that contain a carboxylic acid group () and a ketone group ().Franz Dietrich Klingler, Wolfgang Ebertz "Oxocarboxylic Acids" in Ullmann's Encyclopedia of Industrial Chemistry 2005, Wiley-VCH, Weinheim. In several cases, the keto group is hydrated. The alpha-keto acids are especially important in biology as they are involved in the Krebs citric acid cycle and in glycolysis. Common types of keto acids include: *Alpha-keto acids, alpha-ketoacids, or 2-oxoacids have the keto group adjacent to the carboxylic acid. They often arise by oxidative deamination of amino acids, and reciprocally, they are Precursor (chemistry), precursors to the same. Alpha-keto acids possesses extensive chemistry as acylation agents. Furthermore, alpha-keto acids such as phenylpyruvic acid are endogenous sources for carbon monoxide (as a Gaseous signaling molecules, gasotransmitter) and pharmaceutical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ornithine
Ornithine is a non-proteinogenic amino acid that plays a role in the urea cycle. Ornithine is abnormally accumulated in the body in ornithine transcarbamylase deficiency. The radical is ornithyl. Role in urea cycle L-Ornithine is one of the products of the action of the enzyme arginase on L-arginine, creating urea. Therefore, ornithine is a central part of the urea cycle, which allows for the disposal of excess nitrogen. Ornithine is recycled and, in a manner, is a catalyst. First, ammonia is converted into carbamoyl phosphate (). Ornithine is converted into a urea derivative at the δ (terminal) nitrogen by carbamoyl phosphate synthetase. Another nitrogen is added from aspartate, producing the denitrogenated fumarate, and the resulting arginine (a guanidinium compound) is hydrolysed back to ornithine, producing urea. The nitrogens of urea come from the ammonia and aspartate, and the nitrogen in ornithine remains intact. Ornithine is not an amino acid coded for by DNA, that is, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transamination
Transamination is a chemical reaction that transfers an amino group to a ketoacid to form new amino acids. This pathway is responsible for the deamination of most amino acids. This is one of the major degradation pathways which convert essential amino acids to non-essential amino acids (amino acids that can be synthesized de novo by the organism). Transamination in biochemistry is accomplished by enzymes called transaminases or aminotransferases. α-ketoglutarate acts as the predominant amino-group acceptor and produces glutamate as the new amino acid. :Aminoacid + α-ketoglutarate ↔ α-keto acid + glutamate Glutamate's amino group, in turn, is transferred to oxaloacetate in a second transamination reaction yielding aspartate. :Glutamate + oxaloacetate ↔ α-ketoglutarate + aspartate Mechanism of action Transamination catalyzed by aminotransferase occurs in two stages. In the first step, the α amino group of an amino acid is transferred to the enzyme, producing the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ornithine Aminotransferase
Ornithine aminotransferase (OAT) is an enzyme which is encoded in human by the OAT gene located on chromosome 10. The OAT involved in the ultimate formation of the non-essential amino acid proline from the amino acid ornithine. Ornithine aminotransferase forms the initial intermediate in this process. It catalyzes the reverse reaction as well, and is therefore essential in creating ornithine from the starting substrate proline. Structure The OAT gene encodes for a protein that is approximately 46 kDa in size. The OAT protein is expressed primarily in the liver and the kidney but also in the brain and the retina. The OAT protein is localized to the mitochondrion within the cells where it is expressed. The structure of the OAT protein has been resolved using X-ray crystallography and shows similarity to other subgroup 2 aminotransferases such as dialkyglucine decarboxylatse. The OAT protein functions as a dimer and each monomer consists of a large domain, which contributes mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1-Pyrroline-5-carboxylate Dehydrogenase
In enzymology, a 1-pyrroline-5-carboxylate dehydrogenase () is an enzyme that catalyzes the chemical reaction : (S)-1-pyrroline-5-carboxylate + NAD+ + 2 H2O \rightleftharpoons L-glutamate + NADH + H+ The three substrates of this enzyme are (''S'')-1-pyrroline-5-carboxylate, NAD+, and H2O, whereas its three products are glutamate, NADH, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (''S'')-1-pyrroline-5-carboxylate:NAD+ oxidoreductase. Other names in common use include delta-1-pyrroline-5-carboxylate dehydrogenase, 1-pyrroline dehydrogenase, pyrroline-5-carboxylate dehydrogenase, pyrroline-5-carboxylic acid dehydrogenase, L-pyrroline-5-carboxylate-NAD+ oxidoreductase, and 1-pyrroline-5-carboxylate:NAD+ oxidoreductase. This enzyme participates in glutamate metabolism and arginine and proline metabolism. Structural studies As o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proline Dehydrogenase
In enzymology, proline dehydrogenase (PRODH) ( EC 1.5.5.2, formerly EC 1.5.99.8) is an enzyme of the oxidoreductase family, active in the oxidation of L-proline to (S)-1-pyrroline-5-carboxylate during proline catabolism. The end product of this reaction is then further oxidized in a (S)-1-pyrroline-5-carboxylate dehydrogenase (P5CDH)-dependent reaction of the proline metabolism, or spent to produce ornithine, a crucial metabolite of ornithine and arginine metabolism. The systematic name of this enzyme class is L-proline:quinone oxidoreductase. Other names in common use include L-proline dehydrogenase, L-proline oxidase,and L-proline:(acceptor) oxidoreductase. It employs one cofactor, FAD, which requires riboflavin (vitamin B2). Proline dehydrogenase is in humans encoded by ''PRODH'' and ''PRODH2'' genes, located on the chromosomes 22 and 19, respectively. Their mutations lead to hyperprolinemia, manifested by increased proline levels in blood and urine. The deficiency of PRODH h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrroline-5-carboxylate Reductase
In enzymology, a pyrroline-5-carboxylate reductase () is an enzyme that catalyzes the chemical reaction :L-proline + NAD(P)+ \rightleftharpoons 1-pyrroline-5-carboxylate + NAD(P)H + H+ The 3 substrates of this enzyme are L-proline, NAD+, and NADP+, whereas its 4 products are 1-pyrroline-5-carboxylate, NADH, NADPH, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is L-proline:NAD(P)+ 5-oxidoreductase. Other names in common use include proline oxidase, L-proline oxidase, 1-pyrroline-5-carboxylate reductase, NADPH-L-Delta1-pyrroline carboxylic acid reductase, and L-proline-NAD(P)+ 5-oxidoreductase. This enzyme participates in arginine and proline metabolism. Structural studies As of late 2007, 5 structures have been solved for this class of enzymes, with PDB accession codes , , , , and . Human genes * PYCR1 Pyrroline-5-carboxylate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
