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Preferred IUPAC name (4-Amino-2-methylpyrimidin-5-yl)methanol | |
Other names HMP | |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Within the field of biochemistry, 4-amino-5-hydroxymethyl-2-methylpyrimidine (HMP) also known as toxopyrimidine together with its mono phosphate (HMP-P) and pyrophosphate (HMP-PP) esters are biogenetic precursors to the important biochemical cofactor thiamine pyrophosphate (TPP), a derivative of thiamine (vitamin B1).
HMP, HMP-P and HMP-PP are found along with thiamine forms in a wide variety of living organisms. Thiamine in various salt, formulation and biological matrix forms are used to supplement human and animal diets because these organisms lack the capability to produce it. Methodologies are being sought for biotechnology-based production of thiamine forms and for increasing thiamine content in food sources.
In microorganisms and plants TPP results from coupling of pyrimidine fragment HMP-PP with thiazole fragment HET-P to give thiamine monophosphate, followed by conversion to the pyrophosphate. [1] [2]
Biogenesis of HMP-P and HET-P vary with types of organism.
In bacteria, HMP-P arises by conversion of the purine biosynthetic precursor 5-aminoimidazole ribotide (AIR) through the action of enzymes such as phosphomethylpyrimidine synthase, a member of the radical SAM superfamily. [3] [4] Studies using isotopically labelled AIR have shown which atoms carry into the product. [5] [6] Mechanisms by which this occurs are not yet known with certainty.
In yeasts, HMP-P is derived from metabolites of histidine and pyridoxine. [7] [8] Some of these transformations appear to be catalyzed by radical SAM enzymes. Isotopically labelled precursors have been used to investigate this biogenesis. [5] [9] [10] Mechanisms of the transformations are unknown.
In Salmonella , HMP-P can be derived independently of purine biogenesis when AICAR is available. [11] [12]
In algae, thiamine forms and precursors are scavenged by uptake from water of exogenous products from other organisms. In higher plants, thiamine biogenesis resembles that of bacteria. [2] [13] In some circumstances, thiamine forms and precursors may be obtained through symbiotic relationships with microorganisms in the soil.
Genes relevant for transformations in the biogenesis of HMP-P, HET-P, and TPP have been identified in various organisms and some of the proteins resulting from their expression have been characterized. [14] [15] Biosynthesis of TPP is feedback inhibited through actions of a riboswitch. [16]
Research is ongoing towards understanding biochemistry involved and towards facilitating technologies of socioeconomic value for supply of thiamine in various forms.
Commercially available salts thiamine chloride and thiamine nitrate are produced at scales of thousands of tons annually by chemistry-based manufacturing processes in Europe and Asia. [17] [18] These salts are supplied for formulations for supplementation of human diet and as feed additives for cattle, swine, poultry and fish.
Research for potential biotechnology-based production of thiamine [19] [20] [21] has resulted in patent applications claiming fermentation using recombinant microorganisms modified to deregulate feedback inhibition and allow release of thiamine forms to the media as demonstrated at small scale. [22] [23]
Thiamine forms and their bio-precursors are produced at very large scale in biological matrices such as yeast, grains, plants and meats widely consumed as food and feed. Research into genetic modification of plants. [24] has led to higher levels of thiamine in foodstuffs, such as rice. [25] Use of thiamine forms and their bio-precursors by various means such as seed coating or soil and foliar fertilization to improve plant growth and properties are being investigated. [26]
Nucleotides are organic molecules composed of a nitrogenous base, a pentose sugar and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules within all life-forms on Earth. Nucleotides are obtained in the diet and are also synthesized from common nutrients by the liver.
Thiamine, also known as thiamin and vitamin B1, is a vitamin, an essential micronutrient for humans and animals. It is found in food and commercially synthesized to be a dietary supplement or medication. Phosphorylated forms of thiamine are required for some metabolic reactions, including the breakdown of glucose and amino acids.
B vitamins are a class of water-soluble vitamins that play important roles in cell metabolism and synthesis of red blood cells. They are a chemically diverse class of compounds.
Thiamine pyrophosphate (TPP or ThPP), or thiamine diphosphate (ThDP), or cocarboxylase is a thiamine (vitamin B1) derivative which is produced by the enzyme thiamine diphosphokinase. Thiamine pyrophosphate is a cofactor that is present in all living systems, in which it catalyzes several biochemical reactions.
Thiaminase is an enzyme that metabolizes or breaks down thiamine into pyrimidine and thiazole. It is an antinutrient when consumed.
Phosphoribosyl pyrophosphate (PRPP) is a pentose phosphate. It is a biochemical intermediate in the formation of purine nucleotides via inosine-5-monophosphate, as well as in pyrimidine nucleotide formation. Hence it is a building block for DNA and RNA. The vitamins thiamine and cobalamin, and the amino acid tryptophan also contain fragments derived from PRPP. It is formed from ribose 5-phosphate (R5P) by the enzyme ribose-phosphate diphosphokinase:
Thiamine triphosphate (ThTP) is a biomolecule found in most organisms including bacteria, fungi, plants and animals. Chemically, it is the triphosphate derivative of the vitamin thiamine.
Benfotiamine is a synthetic, fat-soluble, S-acyl derivative of thiamine that is approved in some countries as a medication or dietary supplement to treat diabetic sensorimotor polyneuropathy. Benfotiamine was developed in late 1950s in Japan.
Thiamine monophosphate, also known as ThMP and TMP, is a phosphate ester of thiamine.
Phosphoribosylamine (PRA) is a biochemical intermediate in the formation of purine nucleotides via inosine-5-monophosphate, and hence is a building block for DNA and RNA. The vitamins thiamine and cobalamin also contain fragments derived from PRA.
Phosphoribosyl-N-formylglycineamide is a biochemical intermediate in the formation of purine nucleotides via inosine-5-monophosphate, and hence is a building block for DNA and RNA. The vitamins thiamine and cobalamin also contain fragments derived from FGAR.
The TPP riboswitch, also known as the THI element and Thi-box riboswitch, is a highly conserved RNA secondary structure. It serves as a riboswitch that binds thiamine pyrophosphate (TPP) directly and modulates gene expression through a variety of mechanisms in archaea, bacteria and eukaryotes. TPP is the active form of thiamine (vitamin B1), an essential coenzyme synthesised by coupling of pyrimidine and thiazole moieties in bacteria. The THI element is an extension of a previously detected thiamin-regulatory element, the thi box, there is considerable variability in the predicted length and structures of the additional and facultative stem-loops represented in dark blue in the secondary structure diagram Analysis of operon structures has identified a large number of new candidate thiamin-regulated genes, mostly transporters, in various prokaryotic organisms. The x-ray crystal structure of the TPP riboswitch aptamer has been solved.
In enzymology, a hydroxyethylthiazole kinase is an enzyme that catalyzes the chemical reaction
5′-Phosphoribosyl-5-aminoimidazole is a biochemical intermediate in the formation of purine nucleotides via inosine-5-monophosphate, and hence is a building block for DNA and RNA. The vitamins thiamine and cobalamin also contain fragments derived from AIR. It is an intermediate in the adenine pathway and is synthesized from 5′-phosphoribosylformylglycinamidine by AIR synthetase.
5′-Phosphoribosylformylglycinamidine is a biochemical intermediate in the formation of purine nucleotides via inosine-5-monophosphate, and hence is a building block for DNA and RNA. The vitamins thiamine and cobalamin also contain fragments derived from FGAM.
Glycineamide ribonucleotide is a biochemical intermediate in the formation of purine nucleotides via inosine-5-monophosphate, and hence is a building block for DNA and RNA. The vitamins thiamine and cobalamin also contain fragments derived from GAR.
Sulfur carrier protein ThiS adenylyltransferase is an enzyme with systematic name ATP:(ThiS) adenylyltransferase. This enzyme catalyses the following chemical reaction
Thiazole synthase (EC 2.8.1.10, thiG (gene)) is an enzyme with systematic name 1-deoxy-D-xylulose 5-phosphate:thiol sulfurtransferase. This enzyme catalyses the following chemical reaction
Aminopyrimidine aminohydrolase (EC 3.5.99.2, thiaminase, thiaminase II, tenA (gene)) is an enzyme with systematic name 4-amino-5-aminomethyl-2-methylpyrimidine aminohydrolase. This enzyme catalyses the following chemical reaction
Phosphomethylpyrimidine synthase is an enzyme with systematic name 5-amino-1-(5-phospho-D-ribosyl)imidazole formate-lyase . This enzyme catalyses the following chemical reaction