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.
In biochemistry, a kinase is an enzyme that catalyzes the transfer of phosphate groups from high-energy, phosphate-donating molecules to specific substrates. This process is known as phosphorylation, where the high-energy ATP molecule donates a phosphate group to the substrate molecule. This transesterification produces a phosphorylated substrate and ADP. Conversely, it is referred to as dephosphorylation when the phosphorylated substrate donates a phosphate group and ADP gains a phosphate group. These two processes, phosphorylation and dephosphorylation, occur four times during glycolysis.
Flavins refers generally to the class of organic compounds containing the tricyclic heterocycle isoalloxazine or its isomer alloxazine, and derivatives thereof. The biochemical source of flavin is the vitamin riboflavin. The flavin moiety is often attached with an adenosine diphosphate to form flavin adenine dinucleotide (FAD), and, in other circumstances, is found as flavin mononucleotide, a phosphorylated form of riboflavin. It is in one or the other of these forms that flavin is present as a prosthetic group in flavoproteins.
Vitamin deficiency is the condition of a long-term lack of a vitamin. When caused by not enough vitamin intake it is classified as a primary deficiency, whereas when due to an underlying disorder such as malabsorption it is called a secondary deficiency. An underlying disorder may be metabolic – as in a genetic defect for converting tryptophan to niacin – or from lifestyle choices that increase vitamin needs, such as smoking or drinking alcohol. Government guidelines on vitamin deficiencies advise certain intakes for healthy people, with specific values for women, men, babies, the elderly, and during pregnancy or breastfeeding. Many countries have mandated vitamin food fortification programs to prevent commonly occurring vitamin deficiencies.
Guanosine-5'-triphosphate (GTP) is a purine nucleoside triphosphate. It is one of the building blocks needed for the synthesis of RNA during the transcription process. Its structure is similar to that of the guanosine nucleoside, the only difference being that nucleotides like GTP have phosphates on their ribose sugar. GTP has the guanine nucleobase attached to the 1' carbon of the ribose and it has the triphosphate moiety attached to ribose's 5' carbon.
B vitamins are a class of water-soluble vitamins that play important roles in cell metabolism and synthesis of red blood cells. Though these vitamins share similar names (B1, B2, B3, etc.), they are chemically distinct compounds that often coexist in the same foods. In general, dietary supplements containing all eight are referred to as a vitamin B complex. Individual B vitamin supplements are referred to by the specific number or name of each vitamin, such as B1 for thiamine, B2 for riboflavin, and B3 for niacin. Some are more commonly recognized by name than by number, for example pantothenic acid, biotin, and folate.
In biochemistry, flavin adenine dinucleotide (FAD) is a redox-active coenzyme associated with various proteins, which is involved with several enzymatic reactions in metabolism. A flavoprotein is a protein that contains a flavin group, which may be in the form of FAD or flavin mononucleotide (FMN). Many flavoproteins are known: components of the succinate dehydrogenase complex, α-ketoglutarate dehydrogenase, and a component of the pyruvate dehydrogenase complex.
Flavin mononucleotide (FMN), or riboflavin-5′-phosphate, is a biomolecule produced from riboflavin (vitamin B2) by the enzyme riboflavin kinase and functions as the prosthetic group of various oxidoreductases, including NADH dehydrogenase, as well as cofactor in biological blue-light photo receptors. During the catalytic cycle, a reversible interconversion of the oxidized (FMN), semiquinone (FMNH•), and reduced (FMNH2) forms occurs in the various oxidoreductases. FMN is a stronger oxidizing agent than NAD and is particularly useful because it can take part in both one- and two-electron transfers. In its role as blue-light photo receptor, (oxidized) FMN stands out from the 'conventional' photo receptors as the signaling state and not an E/Z isomerization.
Corneal cross-linking (CXL) with riboflavin (vitamin B2) and UV-A light is a surgical treatment for corneal ectasia such as keratoconus, PMD, and post-LASIK ectasia.
Flavoproteins are proteins that contain a nucleic acid derivative of riboflavin.
Max Tishler (October 30, 1906 – March 18, 1989) was president of Merck Sharp and Dohme Research Laboratories where he led the research teams that synthesized ascorbic acid, riboflavin, cortisone, pyridoxine, pantothenic acid, nicotinamide, methionine, threonine, and tryptophan. He also developed the fermentation processes for actinomycin, vitamin B12, streptomycin, and penicillin. Tishler invented sulfaquinoxaline for the treatment for coccidiosis.
Fazio–Londe disease (FLD), also called progressive bulbar palsy of childhood, is a very rare inherited motor neuron disease of children and young adults and is characterized by progressive paralysis of muscles innervated by cranial nerves.
Lumazine synthase (EC 2.5.1.78, 6,7-dimethyl-8-ribityllumazine synthase, 6,7-dimethyl-8-ribityllumazine synthase 2, 6,7-dimethyl-8-ribityllumazine synthase 1, lumazine synthase 2, lumazine synthase 1, type I lumazine synthase, type II lumazine synthase, RIB4, MJ0303, RibH, Pbls, MbtLS, RibH1 protein, RibH2 protein, RibH1, RibH2) is an enzyme with systematic name 5-amino-6-(D-ribitylamino)uracil butanedionetransferase. This enzyme catalyses the following chemical reaction
Riboflavin synthase is an enzyme that catalyzes the final reaction of riboflavin biosynthesis. It catalyzes the transfer of a four-carbon unit from one molecule of 6,7-dimethyl-8-ribityllumazine onto another, resulting in the synthesis of riboflavin and 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione:
The enzyme FAD-AMP lyase (cyclizing) catalyzes the reaction
In enzymology, a riboflavinase (EC 3.5.99.1) is an enzyme that catalyzes the chemical reaction
In enzymology, a riboflavin kinase is an enzyme that catalyzes the chemical reaction
Paul György (April 7, 1893 – March 1, 1976) was a Hungarian-born American biochemist, nutritionist, and pediatrician best known for his discovery of three B vitamins: riboflavin, B6, and biotin. Gyorgy was also well known for his research into the protective factors of human breast milk, particularly for his discoveries of Lactobacillus bifidus growth factor activity in human milk and its anti-staphylococcal properties. He was a recipient of the National Medal of Science in 1975 from President Gerald Ford.
Post-LASIK ectasia is a condition similar to keratoconus where the cornea starts to bulge forwards at a variable time after LASIK, PRK, or SMILE corneal laser eye surgery. However, the physiological processes of post-LASIK ectasia seem to be different from keratoconus. The visible changes in the basal epithelial cell and anterior and posterior keratocytes linked with keratoconus were not observed in post-LASIK ectasia.
The mitochondrial folate transporter (MTF) is a transport protein that facilitates the transfer of tetrahydrofolate across the inner mitochondrial membrane. It is encoded by the SLC25A32 gene and belongs to the mitochondrial carrier superfamily.
