riboflavin kinase | |||||||||
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Identifiers | |||||||||
EC no. | 2.7.1.26 | ||||||||
CAS no. | 9032-82-0 | ||||||||
Databases | |||||||||
IntEnz | IntEnz view | ||||||||
BRENDA | BRENDA entry | ||||||||
ExPASy | NiceZyme view | ||||||||
KEGG | KEGG entry | ||||||||
MetaCyc | metabolic pathway | ||||||||
PRIAM | profile | ||||||||
PDB structures | RCSB PDB PDBe PDBsum | ||||||||
Gene Ontology | AmiGO / QuickGO | ||||||||
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Riboflavin Kinase | |||||||||
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Identifiers | |||||||||
Symbol | Flavokinase | ||||||||
Pfam | PF01687 | ||||||||
InterPro | IPR015865 | ||||||||
SCOP2 | 1mrz / SCOPe / SUPFAM | ||||||||
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Riboflavin kinase | |||||||||||
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Identifiers | |||||||||||
Symbol | Riboflavin_kinase | ||||||||||
Pfam | PF01687 | ||||||||||
InterPro | IPR015865 | ||||||||||
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In enzymology, a riboflavin kinase (EC 2.7.1.26) is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are ATP and riboflavin, whereas its two products are ADP and FMN.
Riboflavin is converted into catalytically active cofactors (FAD and FMN) by the actions of riboflavin kinase (EC 2.7.1.26), which converts it into FMN, and FAD synthetase (EC 2.7.7.2), which adenylates FMN to FAD. Eukaryotes usually have two separate enzymes, while most prokaryotes have a single bifunctional protein that can carry out both catalyses, although exceptions occur in both cases. While eukaryotic monofunctional riboflavin kinase is orthologous to the bifunctional prokaryotic enzyme, [2] the monofunctional FAD synthetase differs from its prokaryotic counterpart, and is instead related to the PAPS-reductase family. [3] The bacterial FAD synthetase that is part of the bifunctional enzyme has remote similarity to nucleotidyl transferases and, hence, it may be involved in the adenylylation reaction of FAD synthetases. [4]
This enzyme belongs to the family of transferases, to be specific, those transferring phosphorus-containing groups (phosphotransferases) with an alcohol group as acceptor. The systematic name of this enzyme class is ATP:riboflavin 5'-phosphotransferase. This enzyme is also called flavokinase. This enzyme participates in riboflavin metabolism.
However, archaeal riboflavin kinases (EC 2.7.1.161) in general utilize CTP rather than ATP as the donor nucleotide, catalyzing the reaction
Riboflavin kinase can also be isolated from other types of bacteria, all with similar function but a different number of amino acids.
The complete enzyme arrangement can be observed with X-ray crystallography and with NMR. The riboflavin kinase enzyme isolated from Thermoplasma acidophilum contains 220 amino acids. The structure of this enzyme has been determined X-ray crystallography at a resolution of 2.20 Å. Its secondary structure contains 69 residues (30%) in alpha helix form, and 60 residues (26%) a beta sheet conformation. The enzyme contains a magnesium binding site at amino acids 131 and 133, and a Flavin mononucleotide binding site at amino acids 188 and 195.
As of late 2007, 14 structures have been solved for this class of enzymes, with PDB accession codes 1N05, 1N06, 1N07, 1N08, 1NB0, 1NB9, 1P4M, 1Q9S, 2P3M, 2VBS, 2VBT, 3CTA, 2VBU, and 2VBV.
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.
In molecular biology, biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds, or joined to form macromolecules. This process often consists of metabolic pathways. Some of these biosynthetic pathways are located within a single cellular organelle, while others involve enzymes that are located within multiple cellular organelles. Examples of these biosynthetic pathways include the production of lipid membrane components and nucleotides. Biosynthesis is usually synonymous with anabolism.
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.
Flavoproteins are proteins that contain a nucleic acid derivative of riboflavin. These proteins are involved in a wide array of biological processes, including removal of radicals contributing to oxidative stress, photosynthesis, and DNA repair. The flavoproteins are some of the most-studied families of enzymes.
CTP synthase is an enzyme involved in pyrimidine biosynthesis that interconverts UTP and CTP.
Phosphoribosylformylglycinamidine cyclo-ligase is the fifth enzyme in the de novo synthesis of purine nucleotides. It catalyzes the reaction to form 5-aminoimidazole ribotide (AIR) from formylglycinamidine-ribonucleotide FGAM. This reaction closes the ring and produces a 5-membered imidazole ring of the purine nucleus (AIR):
Guanosine monophosphate synthetase, also known as GMPS is an enzyme that converts xanthosine monophosphate to guanosine monophosphate.
In enzymology, a glutamate synthase (NADPH) (EC 1.4.1.13) is an enzyme that catalyzes the chemical reaction
In enzymology, a formate—tetrahydrofolate ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a phosphopantothenate—cysteine ligase also known as phosphopantothenoylcysteine synthetase (PPCS) is an enzyme that catalyzes the chemical reaction which constitutes the second of five steps involved in the conversion of pantothenate to Coenzyme A. The reaction is:
In molecular biology, the protein domain SAICAR synthase is an enzyme which catalyses a reaction to create SAICAR. In enzymology, this enzyme is also known as phosphoribosylaminoimidazolesuccinocarboxamide synthase. It is an enzyme that catalyzes the chemical reaction
In enzymology, a threonine-tRNA ligase is an enzyme that catalyzes the chemical reaction
The enzyme chorismate synthase catalyzes the chemical reaction
In enzymology, a 2-amino-4-hydroxy-6-hydroxymethyldihydropteridine diphosphokinase is an enzyme that catalyzes the chemical reaction
In enzymology, a dephospho-[reductase kinase] kinase is an enzyme that catalyzes the chemical reaction
In enzymology, a dolichol kinase is an enzyme that catalyzes the chemical reaction
In enzymology, a FMN adenylyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, a protein-histidine tele-kinase is an enzyme that catalyzes the chemical reaction
The prokaryotic riboflavin biosynthesis protein is a bifunctional enzyme found in bacteria that catalyzes the phosphorylation of riboflavin into flavin mononucleotide (FMN) and the adenylylation of FMN into flavin adenine dinucleotide (FAD). It consists of a C-terminal riboflavin kinase and an N-terminal FMN-adenylyltransferase. This bacterial protein is functionally similar to the monofunctional riboflavin kinases and FMN-adenylyltransferases of eukaryotic organisms, but only the riboflavin kinases are structurally homologous.
CTP-dependent riboflavin kinase is an enzyme with systematic name CTP:riboflavin 5′-phosphotransferase. This enzyme catalyses the following chemical reaction
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