Riboflavin, also known as vitamin B2, is a vitamin found in food and sold as a dietary supplement. It is essential to the formation of two major coenzymes, flavin mononucleotide and flavin adenine dinucleotide. These coenzymes are involved in energy metabolism, cellular respiration, and antibody production, as well as normal growth and development. The coenzymes are also required for the metabolism of niacin, vitamin B6, and folate. Riboflavin is prescribed to treat corneal thinning, and taken orally, may reduce the incidence of migraine headaches in adults.
Vitamin B6 is one of the B vitamins, and thus an essential nutrient. The term refers to a group of six chemically similar compounds, i.e., "vitamers", which can be interconverted in biological systems. Its active form, pyridoxal 5′-phosphate, serves as a coenzyme in more than 140 enzyme reactions in amino acid, glucose, and lipid metabolism.
A prosthetic group is the non-amino acid component that is part of the structure of the heteroproteins or conjugated proteins, being tightly linked to the apoprotein.
Aminolevulinic acid synthase (ALA synthase, ALAS, or delta-aminolevulinic acid synthase) is an enzyme (EC 2.3.1.37) that catalyzes the synthesis of δ-aminolevulinic acid (ALA) the first common precursor in the biosynthesis of all tetrapyrroles such as hemes, cobalamins and chlorophylls. The reaction is as follows:
Pyridoxal phosphate (PLP, pyridoxal 5'-phosphate, P5P), the active form of vitamin B6, is a coenzyme in a variety of enzymatic reactions. The International Union of Biochemistry and Molecular Biology has catalogued more than 140 PLP-dependent activities, corresponding to ~4% of all classified activities. The versatility of PLP arises from its ability to covalently bind the substrate, and then to act as an electrophilic catalyst, thereby stabilizing different types of carbanionic reaction intermediates.
Purine nucleoside phosphorylase, PNP, PNPase or inosine phosphorylase is an enzyme that in humans is encoded by the NP gene. It catalyzes the chemical reaction
Bisphosphoglycerate mutase is an enzyme expressed in erythrocytes and placental cells. It is responsible for the catalytic synthesis of 2,3-Bisphosphoglycerate (2,3-BPG) from 1,3-bisphosphoglycerate. BPGM also has a mutase and a phosphatase function, but these are much less active, in contrast to its glycolytic cousin, phosphoglycerate mutase (PGM), which favors these two functions, but can also catalyze the synthesis of 2,3-BPG to a lesser extent.
Pyridoxine 5′-phosphate oxidase is an enzyme, encoded by the PNPO gene, that catalyzes several reactions in the vitamin B6 metabolism pathway. Pyridoxine 5′-phosphate oxidase catalyzes the final, rate-limiting step in vitamin B6 metabolism, the biosynthesis of pyridoxal 5′-phosphate, the biologically active form of vitamin B6 which acts as an essential cofactor. Pyridoxine 5′-phosphate oxidase is a member of the enzyme class oxidases, or more specifically, oxidoreductases. These enzymes catalyze a simultaneous oxidation-reduction reaction. The substrate oxidase enzymes is hydroxlyated by one oxygen atom of molecular oxygen. Concurrently, the other oxygen atom is reduced to water. Even though molecular oxygen is the electron acceptor in these enzymes' reactions, they are unique because oxygen does not appear in the oxidized product.
In enzymology, an erythrose-4-phosphate dehydrogenase (EC 1.2.1.72) is an enzyme that catalyzes the chemical reaction
In enzymology, a 4-hydroxythreonine-4-phosphate dehydrogenase (EC 1.1.1.262) is an enzyme that catalyzes the chemical reaction
In enzymology, a pyridoxal 4-dehydrogenase (EC 1.1.1.107) is an enzyme that catalyzes the chemical reaction
The enzyme D-serine ammonia-lyase (EC 4.3.1.18), with systematic name D-serine ammonia-lyase (pyruvate-forming), catalyzes the chemical reaction
The enzyme threonine synthase (EC 4.2.3.1) catalyzes the chemical reaction
The primary biochemical reaction catalyzed by the enzyme adenosylcobalamin/α-ribazole phosphatase (formerly α-ribazole phosphatase) (EC 3.1.3.73) is
In enzymology, a pyridoxine 5'-phosphate synthase (EC 2.6.99.2) is an enzyme that catalyzes the chemical reaction
In enzymology, a pyridoxamine-phosphate transaminase is an enzyme that catalyzes the chemical reaction
In enzymology, a pyridoxal kinase is an enzyme that catalyzes the chemical reaction
Lipid phosphate phosphohydrolase 1 also known as phosphatidic acid phosphatase 2a is an enzyme that in humans is encoded by the PPAP2A gene.
Pyridoxal kinase is an enzyme that in humans is encoded by the PDXK gene.
Megavitamin-B6 syndrome is a collection of symptoms that can result from chronic supplementation, or acute overdose, of vitamin B6. While it is also known as hypervitaminosis B6, vitamin B6 toxicity and vitamin B6 excess, megavitamin-b6 syndrome is the name used in the ICD-10.
