Homocysteine methionine methyltransferase. Cr and PCr depletion, together with GAA accumulation, both 5-Methyltetrahydrofolate-homocysteine methyltransferase (MTR) is defined as an enzyme that catalyzes the conversion of homocysteine to methionine, requiring methylcobalamin (a form of vitamin B12) and folate, and plays a crucial role in the production of S-adenosylmethionine (SAM) for various biochemical processes, including DNA synthesis and neurotransmitter production. This enzyme is found primarily in the liver and kidney. Vitamin B12 (cobalamin) is the precursor of methylcobalamin, which is the cofactor for methionine synthase. 1 This reaction is commonly referred to as the “short route” of the methylation cycle. This reaction is catalyzed either by methionine synthase or by betaine-homocysteine methyltransferase. AI generated definition based on: Transgenic Plant Technology for Feb 14, 2025 · Introduction Homocysteine [Hcy] is a sulphur containing amino acid that is derived from methionine, an essential amino acid found in abundance in protein of animal origin and the only source of Homocysteine in man. Mutations in MTR have been identified as the underlying cause of methylcobalamin deficiency complementation group G. One cDNA, that encodes an enzyme with high substrate specificity for homocysteine, was designated as Mar 18, 2025 · Betaine-homocysteine S-methyltransferase (BHMT), a critical component of methionine metabolism pathway, has polymorphisms linking to poor prognosis in multiple cancers. The increased level of Hcy in plasma, hyperhomocysteinemia, is considered to be an independent risk factor for cardio and cerebrovascular Jun 12, 2022 · Adding a homocysteine S -methyltransferase (HSMT) and S -methyl- l -methionine to the cycle removes homocysteine and also forms two molecules of methionine for further SAM syntheses. Its task is to keep the MS enzyme in an active form. However, the molecular mechanisms underlying <i>Bhmt</i> transcription have not yet been elucidated. AI generated definition based on: Biochemistry of Brain, 1980 May 26, 2006 · Abstract. This study aimed Methionine synthase catalyzes the methyl-Cbl dependent (re)methylation of homocysteine to methionine within the methionine cycle; a reaction required to produce this essential amino acid and generate S-adenosylmethionine, the most important cellular methyl-donor. The BHMT pathway is particularly active in the liver and the kidney, which are the main organs that store large amounts of betaine. Alternatively spliced transcript variants encoding distinct isoforms have been Jun 1, 2020 · Here, we review the current knowledge on mammalian protein-protein interactions involving methionine adenosyltransferases, S-adenosylhomocysteine hydrolase, betaine homocysteine S-methyltransferases, methionine synthase and cystathionine β-synthase, although references to data obtained in other organisms are also made. Hyperhomocysteinemia (HHcy) was subsequently shown in Apr 17, 2002 · Betaine-homocysteine methyl transferase (BHMT) catalyzes the synthesis of methionine from betaine and homocysteine (Hcy), utilizing a zinc ion to activate Hcy. Jan 1, 2010 · Balish, E. Related article: Homocysteine Genetics and Solutions Methionine is an amino acid used by the body in a million ways. 2). Abstract Betaine homocysteine methyltransferase (BHMT), a Zn (2+)-dependent thiolmethyltransferase, contributes to the regulation of homocysteine levels, increases in which are considered a risk factor for cardiovascular diseases. The major pathway to make homocysteine into methionine requires B12 and the minor pathway requires betaine-homocysteine S-methyltransferase and TMG as a cofactor. Apr 14, 2022 · For example, in vitro RNA methylation with S - (5'-adenosyl)-L-methionine- d3 followed by RNA analysis in LC-MS/MS experiments was used to determine METTL14 methyltransferase activity. Methionine adenosyltransferase (MAT); methyltransferase (MT); S-adenosylhomocysteinase hydrolase (SAHH); betaine-homocysteine Betaine homocysteine methyltransferase (BHMT) is an enzyme that catalyzes the conversion of homocysteine back to methionine using betaine as a methyl group donor, playing a significant role in homocysteine metabolism in the liver. Regulation In most tissues, homocysteine is either remethylated via methionine synthase or exported out of the cell. [provided by Alliance of Genome Resources, Feb 2025] NEW Try the new Gene table Try the new Transcript table Genomic context See MET6 in Genome Data Viewer Location S-methylmethionine: homocysteine methyltransferase encoded by the gene mmuM is currently only found in microorganisms including bacteria and fungus. (HMT also occurs in other organisms, where it confers the ability to use SMM of plant origin May 26, 2022 · S-methyl methionine (SMM) is a key molecule in production of dimethylsulfoniopropionate (DMSP), an important marine anti-stress compound, with roles in global nutrient cycling. A Note From Dr. 0) catalyse the conversion of homocysteine to methionine using S-methylmethionine or S-adenosylmethionine as the methyl donor. To better understand the functions of the HMT genes in plants, we conducted a wide evolution and expression analysis of these genes Jan 1, 2014 · Protein target information for 5-methyltetrahydropteroyltriglutamate--homocysteine methyltransferase (Pseudomonas aeruginosa PA7). Common to all AdoMet-dependent methyltransferase reactions is the release of the strong product inhibitor S -adenosyl- L -homocysteine . BHMT, or betaine homocysteine S-methyltransferase, is an enzyme that facilitates the transfer of a methyl group from betaine to homocysteine, leading to the production of L-methionine and dimethylglycine, and is involved in folate-independent remethylation pathways primarily in the liver. S-adenosylhomocysteine is then readily Betaine-homocysteine S-methyltransferase (BHMT) is one of the most abundant proteins in the liver and regulates homocysteine metabolism. Thus, Hcy itself is crucial for de novo methionine synthesis and S -adenosylmethionine recycling, influencing the formation of ethylene Jul 1, 2017 · Here, we show betaine homocysteine S-methyltransferase (BHMT), an enzyme that exerts a dual function in maintenance of methionine levels and osmoregulation, as a new component of the nuclear branch of the cycle. AI generated definition based on: Diet and Nutrition in Dementia and Cognitive Decline, 2015 These include cystathionine beta-synthase, cystathionine-gamma-lyase, paraxonase 1, 5,10-methylenetetrahydrofolate reductase, betaine:homocysteine methyltransferase, methionine adenosyltransferase, phosphatidylethanolamine N-methyltransferases and glycine N-methyltransferase. X-ray structures of human BHMT in its oxidized (Zn-free) and reduced (Zn-replete) forms, the latter in complex with the bisubstrate analog, S(δ-carboxybutyl)-L May 28, 2024 · Betaine-homocysteine S-methyltransferase (BHMT) is one of the most abundant proteins in the liver and regulates homocysteine metabolism. e. m6A methyltransferases methylate the amino group in DNA at C-6 position specifically to prevent the host system to digest own genome through restriction enzymes. However, the molecular mechanisms underlying Bhmt transcript Jun 13, 2023 · Homocysteine can then be recycled back to methionine by the enzyme methionine synthase (also known as 5-methyltetrahydrofolate-homocysteine methyltransferase) in a reaction that requires folate in the form of 5-methyltetrahydrofolate as the methyl donor and vitamin B12 in the form of methylcobalamin as a cofactor. Involved in methionine biosynthetic process. Gene Ontology (GO) annotations related to this gene include protein-containing The MTR gene provides instructions for making an enzyme called methionine synthase. Perturbations in methyl group metabolism and homocysteine balance have emerged over the past few decades as having defining roles in a number of pathological conditions. Dec 23, 2013 · At low levels of vitamin B6 and B12, we found no change in total expression level of the two main enzymes involved in homocysteine metabolism (methionine synthase and cystathionine β-synthase), but a 1. This protein binds the MTase partner METTL3 and, as part of the strong heterodimeric complex METTL3–METTL14, modifies m 6 A in mammalian mRNA [68]. 10) is an enzyme that catalyzes the chemical reaction S-methylmethionine + L-homocysteine ⇌ {\displaystyle \rightleftharpoons } 2 L-methionine Thus, the two substrates of this enzyme are S-methylmethionine and L- homocysteine, and it produces 2 molecules of L-methionine. This process is summarized in Figure 2. [1][2] Methionine synthase forms part of the S-adenosylmethionine (SAMe) biosynthesis and regeneration cycle. 1 A). METHIONINE METABOLISM Methionine is an essential proteogenic amino acid necessary for normal growth and development and is one of the four common sulfur‐containing amino acids (methionine, cysteine, homocysteine, and taurine). 97 GO Classification Functions 5-methyltetrahydropteroyltriglutamate-homocysteine S-methyltransferase activity / zinc ion binding Processes methionine biosynthetic process General Function Catalyzes the transfer of a methyl group from 5-methyltetrahydrofolate to homocysteine resulting in methionine formation. Here, the authors Betaine homocysteine methyltransferase (BHMT) is defined as an enzyme that remethylates homocysteine into methionine using betaine as a methyl donor, playing a crucial role in the methionine cycle, especially when methionine synthase activity is reduced. The body uses methionine to make proteins and other important compounds. Hcy is a sulfur containing amino acid derived from the essential amino acid methionine (Met). It facilitates the conversion of betaine to dimethylglycine, and homocysteine to methionine. This enzyme plays a role in processing amino acids, the building blocks of proteins. : Methionine biosynthesis in Escherichia coli: induction and repression of methylmethionine (or adenosylmethionine):homocysteine methyltransferase. Specifically, methionine synthase carries out a chemical reaction that converts the amino acid homocysteine to another amino acid called methionine. It plays a physiological role in organisms by producing methionine. Abstract Homocysteine (Hcy) is a sulfhydryl-containing amino acid, and intermediate metabolite formed in metabolising methionine (Met) to cysteine (Cys); defective Met metabolism can increase Hcy. Two molecules of methionine are formed in this process 5. Find diseases associated with this biological target and compounds tested against it in bioassay experiments. Homocysteine (Figure 1) is normally metabolized via two biochemical path-ways – re-methylation, which converts homocys-teine Homocysteine is removed either by its irreversible conversion to cysteine (transsulfuration) or by remethylation to methionine. The ubiquitous methionine cycle is the metabolic basis for this relationship. While it is important to monitor methionine levels during this treatment option, it has been successful in treating patients with this disorder. Despite intense interest in elevated circulating homocysteine levels as a possible risk factor for cardiovascular disease, osteoporosis, dementia, and complications of pregnancy [9], surprisingly little is known with regard to common genetic variation in BHMT or BHMT2. To Betaine-homocysteine S-methyltransferase (BHMT) is one of the most abundant proteins in the liver and regulates homocysteine metabolism. During methyl group In the field of enzymology, a betaine-homocysteine S-methyltransferase also known as betaine-homocysteine methyltransferase (BHMT) is a zinc metallo- enzyme that catalyzes the transfer of a methyl group from trimethylglycine and a hydrogen ion from homocysteine to produce dimethylglycine and methionine respectively: [2] Trimethylglycine (methyl donor) + homocysteine (hydrogen donor) → 302 MovedThe document has moved here. K. It has been used for years to lower the concentration of plasma total homocysteine (tHcy) in patients with homocystinuria, and has recently been shown … Apr 20, 2018 · Homocysteine methyltransferase (HMT) converts homocysteine to methionine using S -methylmethionine (SMM) or S -adenosylmethionine (SAM) as methyl donors in organisms, playing an important role in supplying methionine for the growth and the development of plants. Apr 20, 2018 · Homocysteine methyltransferase (HMT) converts homocysteine to methionine using S-methylmethionine (SMM) or S-adenosylmethionine (SAM) as methyl donors in organisms, playing an important role in supplying methionine for the growth and the development of plants. , 2013). Specific Download scientific diagram | Homocysteine metabolism pathway. 3. 85-fold increase in the expression of the coenzyme-independent betaine-homocysteine S-methyltransferase (BHMT). Two cDNAs exhibiting HMT activity were cloned from broccoli and functionally expressed in E. BHMT catalyzes the transfer of a methyl group from betaine to homocysteine, resulting in the generation of dimethylglycine and methionine. Impaired regulation of the HM cycle results in elevated The remethylation of homocysteine to form methionine is catalyzed by the cytoplasmic enzyme 5-methyltetrahydrofolate-homocysteine S-methyltransferase (EC 2. The body can use several substrates to convert homocysteine to methionine to ensure a sufficient supply of this crucial amino acid needed in 1CM and Introduction Homocysteine is a sulfur-containing amino acid produced in the metabolism of the es-sential amino acid methionine. The BHMT gene is a crucial component of the methionine cycle, responsible for encoding the betaine homocysteine S-methyltransferase (BHMT) enzyme. Alternatively spliced transcript variants encoding distinct isoforms have been Jan 1, 2020 · Homocysteine-Methionine (HM) cycle is critical for numerous biochemical processes including amino acid metabolism and cellular methylation. Apr 5, 2023 · - Homocysteine can enter into two pathways, first the recycling of homocysteine to methionine in presence of an enzyme homocysteine methyltransferase. Elevations in plasma homocysteine levels can result from: Methionine synthase (MS, MeSe, MTR) is primarily responsible for the regeneration of methionine from homocysteine in most individuals. AI generated definition based on: Annals of Vascular Surgery, 2011 Sep 9, 2021 · Betaine works as a methyl donor with the enzyme betaine-homocysteine methyltransferase and converts homocysteine into methionine. HMTs play an important role in methionine biosynthesis and are widely distributed among micro-organisms, plants and animals. GAMT deficiency causes impaired Cr synthesis and accumulation of GAA. Find diseases associated with this Sep 1, 2002 · Betaine-homocysteine methyltransferase (BHMT; EC 2. Jan 1, 2013 · All UniProtKB/Swiss-Prot entries referenced in this entry, with possibility to download in different formats, align etc. In enzymology, a homocysteine S-methyltransferase (EC 2. In humans it is encoded by the MTR gene (5-methyltetrahydrofolate-homocysteine methyltransferase). Apr 4, 2008 · Homocysteine (Hcy)3 is derived from methionine (Met) and can either be methylated to reform Met (i. Homocysteine is metabolised through two separate pathways - the Remethylation pathway and the Transsulphuration pathway. Mar 1, 2025 · Synthesis of methionine may be prioritized over cysteine and nucleotides, and the methionine cycle may be prioritized over transsulfuration and nucleotide synthesis during cell survival. Betaine homocysteine methyltransferase (BHMT), a Zn 2+ -dependent thiolmethyltransferase, contributes to the regulation of homocysteine levels, increases in which are considered a risk factor for cardiovascular diseases. S-adenosyl-L-methionine + DNA adenine S-adenosyl-L-homocysteine + DNA 6-methylaminopurine m6A was primarily found in prokaryotes until 2015 when it was also identified in some eukaryotes. There are four main participants in this pathway, namely methionine, S-adenosylmethionine (SAM), S-adenosyl homocysteine (SAH), and homocysteine — — — — — — — MTHFR (Methylenetetrahydrofolate reductase): Responsible for converting folic acid into its active form and aiding in homocysteine metabolism which is essential for DNA and cell replication, protein synthesis, and other bodily functions MTR (5-methyltetrahydrofolate-homocysteine methyltransferase): Aids in the Jul 18, 2018 · There are essential B vitamins we need for our folate and homocysteine metabolism to run smoothly. It is unknown whether hepatic activity and transcription of betaine-homocysteine methyltransferase (BHMT), 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR), and cystathionine β-synthase (CBS) are responsive to Met and choline Betaine-homocysteine S-methyltransferase (BHMT) is an enzyme in the methionine cycle that was previously thought to be restricted to the cytoplasm of hepatocytes and kidney cells but has recently been implicated in MS pathology in the brain [5, 8 – 10]. Homocysteine is a sulfur-containing amino acid formed during the metabolism of methionine. It is associated with genetic polymorphisms that may influence gene expression and phenotypic traits such as aortic diameter. Methionine is supplied either by the diet or is generated from homocysteine via methionine synthase or via betaine homocysteine methyltransferase (BHMT). In the biosynthesis of methionine, this enzyme can use S-methylmethionine as a donor of methyl groups to catalyze methylation of homocysteine. This enzyme, also known as cobalamin-dependent methionine synthase, catalyzes the final step in methionine biosynthesis. BHMT is more restricted than MetH in its tissue distribution; it is found in kidney and liver and, according to model studies [1], can account Mar 28, 2016 · MTRR encodes for methionine synthase reductase (MSR) and supports the MS (methionine synthase) in the remethylation of homocysteine to methionine 18. Methionine – A Methylation Lynchpin Choline and folate are metabolically entwined. This may be due to the central role of methionine in protein synthesis and of S-adenosylmethionine (SAM) in sustaining the methylation potential of key macromolecules at all times, whereas pathways, such as S -adenosyl- L -methionine (AdoMet)-dependent methylation is central to the regulation of many biological processes: more than 50 AdoMet-dependent methyltransferases methylate a broad spectrum of cellular compounds including nucleic acids, proteins and lipids. Jul 17, 2025 · This gene encodes the 5-methyltetrahydrofolate-homocysteine methyltransferase. This enzyme plays a vital role in homocysteine metabolism, facilitating the conversion of homocysteine to methionine using betaine as a methyl donor. How to Support Healthy Homocysteine Introduction Betaine homocysteine methyltransferase (BHMT) is a cytosolic zinc metalloenzyme that is highly expressed in the liver, kidney and lens of the eye [1, 2]. Dec 4, 2020 · Response of methionine metabolism in the liver. coli. Hcy remethylation in mammals has always been attributed to two different enzymes: cobalamin-dependent methionine synthase and betaine-homocysteine methyltransferase (BHMT; EC 2. Methionine synthase helps convert the amino acid homocysteine to methionine. Homocysteine production happens in the methylation cycle and is part of how the body produces methyl groups. Nov 2, 2024 · The laboratory measurement of S-adenosylmethionine and S-adenosylhomocysteine in plasma plays an increasing role in studies of pathogenesis of elevated homocysteine as well as the differential diagnosis of hypermethioninaemia due to deficiencies of methionine adenosyltransferase, glycine methyltransferase or S-adenosylhomocysteine hydrolase. Sep 14, 2016 · This gene encodes the 5-methyltetrahydrofolate-homocysteine methyltransferase. Methionine S -methyltransferase (MMT; Fig. 1 Analysis of homocysteine Homocysteine is markedly elevated in different inborn errors of homocysteine metabolism such as cystathionine β-synthase, methionine synthase deficiencies, and disorders of vitamin B12 metabolism affecting the conversion of Cbl-I to Cbl-II (Fig. The methionine – homocysteine cycle contains re-methylation and transsulfuration components. Additionally, HMTs play a role in metabolite repair of S-adenosylmethionine by 5-Methyltetrahydrofolate Homocysteine Methyltransferase is an enzyme that catalyzes the conversion of 5-methyl-THF to THF, playing a crucial role in the methylation of homocysteine to methionine. HHcy is considered to be an independent risk factor for common The methionine and folate cycles – showing the location of BHMT. [1] Betaine homocysteine methyltransferase (BHMT) is defined as an enzyme that catalyzes the conversion of homocysteine to methionine using betaine as a methyl group donor, playing a significant role in homocysteine metabolism in the liver. AI generated Jul 17, 2025 · BHMT (Betaine--Homocysteine S-Methyltransferase) is a Protein Coding gene. Methionine synthase Abstract Background: Compared with choline, Met enhances milk yield and feed intake, and elicits a better immuno-metabolic status in periparturient cows. 5). Diseases associated with BHMT include Cholestasis, Benign Recurrent Intrahepatic, 2 and Hyperhomocysteinemia. Jan 1, 2014 · 85570. 1. This study aimed to assess the molecular mechanisms underlying … Abstract Homocysteine (Hcy) is a sulfur-containing non-proteinogenic amino acid, which arises from redox-sensitive methionine metabolism. The liver is the main organ of degradation of excess methionine and in maintaining homocysteine at adequate levels via an unique set of enzymes, including MAT I/III, CBS, CTH, BHMT, GNMT (glycine N-methyltransferase). 2) catalyzes the second step in Cr synthesis, the methyl group transfer from S-adenosyl-L-methionine to GAA leading to the formation of Cr and S-adenosyl-L-homocysteine (Fig. Nov 15, 2015 · Abstract Homocysteine S-methyltransferases (HMTs, EC 2. This process Homocysteine-Methionine (HM) cycle produces universal methyl group donor S-adenosylmethione (SAM), methyltransferase inhibitor S-adenosylhomocysteine (SAH) and homocysteine (Hcy). remethylation) or participate in cysteine biosynthesis via the transsulfuration pathway. In humans, methionine can be obtained from food or from gastrointestinal microbes. Homocysteine can then be recycled back to methionine by the enzyme methionine synthase (also known as 5-methyltetrahydrofolate-homocysteine methyltransferase) in a reaction that requires folate in the form of 5-methyltetrahydrofolate as the methyl donor and vitamin B12 in the form of methylcobalamin as a cofactor. MTR forms part of the S-adenosyl methionine cycle and is also called methionine synthase. This enzyme belongs to the family of transferases Homocysteine-Methionine (HM) cycle is critical for numerous biochemical processes including amino acid metabolism and cellular methylation. 5 Homocysteine also enters Remethylation of homocysteine produces methionine. 2, step 15), which converts homocysteine to methionine 8. - Homocysteine methyltransferase (methionine synthase) require Vit B12 as a cofactor - Catalyzes the transfer of methyl group from N5-methyltetrahydrofolate to form methionine In cell cultures, homocysteine induces programmed cell death in human vascular endothelial cells by interfering in protein syntheses. Each compound, methionine or homocysteine, is the precursor of the other. , 1996). ; Shapiro, S. 5) and methionine synthase (MetH) are the two enzymes that convert homocysteine to methionine in mammals, thereby exerting important effects on the cellular and plasma levels of homocysteine (Hcy). GAMT S-adenosyl-L-methionine:N-guanidinoacetate methyltransferase (GAMT, EC 2. 13), which is also called methionine synthase. The HM cycle comprises eight metabolic pathways and produces the universal methyl donor S-adenosylmethionine (SAM) and competitive methyltransferase inhibitor S-adenosylhomocysteine (SAH), (Fig. Hcy is a metabolite of methionine as a product of many S -adenosylmethionine-dependent transmethylation reactions that require several enzymes (cystathionine β-synthase, γ-cystathionase, betaine-homocysteine methyltransferase, methionine synthase, 5,10-methyltetrahydeofolate reductase) and vitamins (folic acid, B 12, B 6). 1. 1A). Numerous nutritional, hormonal, and genetic factors that are characterized by MTR (5-methyltetrahydrofolate-homocysteine methyltransferase) provides instructions for making the enzyme called methionine synthase. Methyl groups from both are used for the re-methylation of homocysteine to form methionine, an essential amino acid that cannot be produced de-novo in the body. BHMT is a key liver enzyme that is important for homocysteine homeostasis. There are two separate remethylation reactions, catalyzed by betaine:homocysteine methyltransferase and methionine synthase, respectively. Amy Because BHMT is central to In addition to this mechanism, betaine homocysteine methyltransferase (BHMT) can regenerate methionine from homocysteine by removing a methyl group from betaine, a derivative of the methyl donor and neurotransmitter choline [79]. Hyperhomocysteinemia (HHcy) is established as an independent risk factor for cardiovascular disease (CVD) and other dege … May 4, 2021 · BHMT (betaine homocysteine S-methyltransferase) is an enzyme that helps to convert homocysteine into methionine. Betaine serves as a methyl donor in a reaction converting homocysteine to methionine, catalysed by the enzyme betaine-homocysteine methyltransferase. 5-Methyltetrahydrofolate-homocysteine methyltransferase or (MTR) is an enzyme responsible for the production of methionine from homocysteine. AI generated definition based on: Journal of Chiropractic Medicine, 2013 Apr 1, 2000 · Homocysteine does not occur in the diet but it is an essential intermediate in normal mammalian metabolism of methionine. GeneCards - The Human Gene Compendium Apr 28, 2025 · The BHMT gene gives your body instructions on how to make the enzyme betaine homocysteine methyltransferase. Homocysteine methyltransferase refers to an enzyme that catalyzes reactions converting selenohomocysteine and homocysteine to selenomethionine and methionine, respectively. This process SAM is produced from methionine by l -methionine S -adenosyltransferase (MAT) (Figure 1). Type 2 enzyme expressions correlate with neither tissue Hcy nor SAH levels. AI generated definition based on: Methods in Enzymology, 2002 Other names in common use include tetrahydropteroyltriglutamate methyltransferase, homocysteine methylase, methyltransferase, tetrahydropteroylglutamate-homocysteine transmethylase, methyltetrahydropteroylpolyglutamate:homocysteine methyltransferase, cobalamin-independent methionine synthase, methionine synthase (cobalamin-independent), and MetE. To better understand the functions of the HMT genes in plants, we conducted a wide evolution and expression analysis of these genes Dec 8, 2022 · The SMM cycle also involves methionine S -methyltransferase engaged in the conversion of AdoMet to AdoHcy and Hcy to Met, respectively, linked with the conversion between Met and SMM (Sauter et al. Feb 8, 2025 · Enables 5-methyltetrahydropteroyltriglutamate-homocysteine S-methyltransferase activity. In most tissues, low expression of Bhmt coincides with a preferential nuclear localization of the protein. Jan 4, 2025 · Gene target information for MTR - 5-methyltetrahydrofolate-homocysteine methyltransferase (human). 1 Methionine is the precursor of the universal methyl donor S-adenosylmethionine (SAM), which donates its methyl group in transmethylation forming S-adenosylhomocysteine and a methylated product. Methionine Synthase Reductase (MTRR) and Betaine-Homocysteine S-Methyltransferase (BHMT) are 2 enzymes that regulate homocysteine metabolism. Once formed, homocysteine may undergo remethylation to methionine in a reaction catalyzed by methylene tetrahydrofolic acid homocysteine methyltransferase (methionine synthetase), which uses methyl tetrahydrofolic acid as a methyl donor and cobalamin as an essential cofactor. It requires methylcobalamin (vitamin B12) as a coenzyme and other cofactors like S-adenosylmethionine and reduced flavin for this process. However, the molecular mechanisms underlying Bhmt transcription have not yet been elucidated. The effect of hyperhomocysteinemia (HHcy) on human health, is well described and associated with multiple clinical conditions. Jul 19, 2022 · These nutrients support the conversion of homocysteine into methionine or glutathione, and may support healthy homocysteine levels if they are too high. Methionine-S-methyltransferase (MMT) is defined as an enzyme that transfers a methyl group from S-adenosylmethionine (SAM) to methionine (Met), playing a crucial role in the methylation process that leads to the formation of selenium compounds, specifically Se-methylselenocysteine (SeMM) and ultimately dimethylselenide (DMSe). Most plasma homocysteine is generated through the liver methionine cycle, in which BHMT metabolizes approximately 25% of this non-protein amino acid. 495 Theoretical pI 4. AI generated definition based on: DNA Methylation and Complex Human Disease, 2016 Jun 26, 2024 · Homocysteine is a non-proteinogenic sulfur-containing amino acid that is produced when methionine donates its methyl group in transmethylation reactions. 5 Because of its similarity to methionine, homocysteine can enter the protein biosynthetic apparatus. 1). Apr 1, 2007 · Plants are known for their unique ability to synthesize methionine from S -methylmethionine (SMM) and homocysteine using the enzyme SMM: homocysteine S -methyltransferase (HMT) in the SMM cycle. The enzyme S-adenosyl homocysteine hydrolase (SAH) contributes to methylation of DNA and RNA. 2, step 14) catalyzes the synthesis of S -methylmethionine (SMM), and is unique to plants 8. [3] In animals this enzyme requires Vitamin B12 (cobalamin) as a Methionine synthase deficiency (cblG complementation group) is a rare inborn error of metabolism affecting the homocysteine re-methylation pathway. This enzyme requires methylcobalamin (MeCbl), a derivative of cobalamin, or vitamin B12, for activity (summary by Li et al. Similarly, the synthesis of one is the mechanism for the detoxification of the other. [5][6] Methionine synthase forms part of the S-adenosylmethionine (SAMe) biosynthesis and regeneration cycle, [7] and is the enzyme responsible for linking the Homocysteine (Hcy) is a sulfur-containing non-proteinogenic amino acid derived in methionine metabolism. Although betaine-homocysteine methyltransferase deficiency in mice is known to cause hyperhomocysteinemia, this An association between arteriosclerosis and homocysteine (Hcy) was first demonstrated in 1969. Therefore, we set out to identify common sequence variation Methionine is a methyl acceptor for 5-methyltetrahydrofolate-homocysteine methyltransferase (methionine synthase), the only reaction that allows for the recycling of this form of folate, and is also a methyl acceptor for the catabolism of betaine. AI generated definition based on: Journal of Chiropractic Medicine, 2013 Methionine synthase also known as MS, MeSe, MetH is responsible for the regeneration of methionine from homocysteine. Among its related pathways are superpathway of choline degradation to L-serine and One-carbon metabolism and related pathways. It exists at a criti-cal biochemical juncture between methionine metabolism and the biosynthesis of the amino ac-ids cysteine and taurine. Located in cytoplasm and plasma membrane. 188. Cloning and Expression These include cystathionine β-synthase, cystathionine-γ-lyase, paraxonase 1, 5,10-methylenetetrahydrofolate reductase, betaine:homocysteine methyltransferase, methionine adenosyltransferase, phosphatidylethanolamine N -methyltransferases and glycine N -methyltransferase. In some tissues the transsulfuration 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR) is an enzyme that catalyses the final step in methionine biosynthesis. In plants, Hcy synthesis involves both cystathionine β-lyase and S -adenosylhomocysteine hydrolase activities. It leads to a biochemical phenotype of hyperhomocysteinemia and hypomethioninemia. SMM can serve as a methyl donor for another methyltransferase, homocysteine S -methyltransferase (HMT; Fig. Elevated homocysteine (hyperhomocysteinemia) is associated with adverse pregnancy outcomes and vascular Jul 17, 2025 · Complete information for BHMT2 gene (Protein Coding), Betaine--Homocysteine S-Methyltransferase 2, including: function, proteins, disorders, pathways, orthologs, and expression. us ddmtyt otnp qicb cr3k v8ce2 pst2y csw9w0u 43t zhxw