Gene Association: METTL18
UniProt Search:
METTL18 (PROTEIN_CODING)
Function Description: methyltransferase 18, RPL3 N3(tau)-histidine
found 6 associated metabolites with current gene based on the text mining result from the pubmed database.
1-Methylhistidine
1-Methylhistidine, also known as 1-MHis or 1MH, belongs to the class of organic compounds known as histidine and derivatives. 1MH is also classified as a methylamino acid. Methylamino acids are primarily proteogenic amino acids (found in proteins) which have been methylated (in situ) on their side chains by various methyltransferase enzymes. Histidine can be methylated at either the N1 or N3 position of its imidazole ring, yielding the isomers 1-methylhistidine (1MH; also referred to as pi-methylhistidine) or 3-methylhistidine (3MH; tau-methylhistidine), respectively. There is considerable confusion with regard to the nomenclature of the methylated nitrogen atoms on the imidazole ring of histidine and other histidine-containing peptides such as anserine. In particular, older literature (mostly prior to the year 2000) designated anserine (Npi methylated) as beta-alanyl-N1-methyl-histidine, whereas according to standard IUPAC nomenclature, anserine is correctly named as beta-alanyl-N3-methyl-histidine. As a result, many papers published prior to the year 2000 incorrectly identified 1MH as a specific marker for dietary consumption or various pathophysiological effects when they really were referring to 3MH (PMID: 24137022). Recent discoveries have shown that 1MH is produced in essentially all mammals (and other vertebrates) via the enzyme known as METTL9 (PMID: 33563959). METTL9 is a broad-specificity methyltransferase that mediates the formation of the majority of 1MH present in mammalian proteomes. METTL9-catalyzed methylation requires a His-x-His (HxH) motif, where "x" is a small amino acid. This HxH motif is found in a number of abundant mammalian proteins such as ARMC6, S100A9, and NDUFB3 (PMID: 33563959). Because of its abundance in many muscle-related proteins, 1MH has been found to be a good biomarker for the consumption of meat (PMID: 21527577). Dietary studies have shown that poultry consumption (p-trend = 0.0006) and chicken consumption (p-trend = 0.0003) are associated with increased levels of 1MH in human plasma (PMID: 30018457). The consumption of fish, especially salmon and cod, has also been shown to increase the levels of 1MH in serum and urine (PMID: 31401679). As a general rule, urinary 1MH is associated with white meat intake (p< 0.001), whereas urinary 3MH is associated with red meat intake (p< 0.001) (PMID: 34091671). 1-Methyl-L-histidine is an objective indicator of meat ingestion and exogenous 3-methylhistidine (3MH) intake. 1-Methyl-L-histidine is an objective indicator of meat ingestion and exogenous 3-methylhistidine (3MH) intake. 3-Methyl-L-histidine is a biomarker for meat consumption, especially chicken. It is also a biomarker for the consumption of soy products.
3-Methylhistidine
3-Methylhistidine, also known as 3-MHis or 3MH, belongs to the class of organic compounds known as histidine and derivatives. 3MH is also classified as a methylamino acid. Methylamino acids are primarily proteogenic amino acids (found in proteins) which have been methylated (in situ) on their side chains by various methyltransferase enzymes. 3-Methylhistidine is also classified as a member of the class of compounds known as L-alpha-amino acids. L-alpha-Amino acids are alpha amino acids which have the L-configuration of the alpha-carbon atom. Amino acids are organic compounds that contain amino (–NH2) and carboxyl (–COOH) functional groups, along with a side chain (R group) specific to each amino acid. 3-Methylhistidine is generated from histidine residues found in proteins. Histidine can be methylated at either the N1 or N3 position of its imidazole ring, yielding the isomers 1-methylhistidine (1MH; also referred to as pi-methylhistidine) or 3-methylhistidine (3MH; tau-methylhistidine), respectively. There is considerable confusion with regard to the nomenclature of the methylated nitrogen atoms on the imidazole ring of histidine and other histidine-containing peptides such as anserine. In particular, older literature (mostly prior to the year 2000) designated anserine (Npi methylated) as beta-alanyl-N1-methyl-histidine, whereas according to standard IUPAC nomenclature, anserine is correctly named as beta-alanyl-N3-methyl-histidine. As a result, many papers published prior to the year 2000 incorrectly identified 1MH as a specific marker for dietary consumption or various pathophysiological effects when they really were referring to 3MH (PMID: 24137022). Histidine methylation on the 3- or tau site is mediated by the enzyme known as METTL18. METTL18 is a nuclear methyltransferase protein that contains a functional nuclear localization signal and accumulates in nucleoli. Urinary concentrations of 3-methylhistidine can be used as a biomarker for skeletal muscle protein breakdown in humans who have been subject to muscle injury (PMID: 16079625). 3-methylhistidine is formed by the posttranslational methylation of histidine residues of the main myofibrillar proteins actin and myosin. During protein catabolism, 3-methylhistidine is released but cannot be reutilized. Therefore, the plasma concentration and urine excretion of 3-methylhistidine are sensitive markers of myofibrillar protein degradation (PMID: 32235743). Approximately 75\\\% of 3-methylhistidine is estimated to originate from skeletal muscle (PMID: 32235743). In addition to the degradation of muscle proteins, the 3-methylhistidine level is affected by the degradation of intestinal proteins and meat intake. 3-Methylhistidine exists in all eukaryotes, ranging from yeast to humans. In humans, 3-methylhistidine is involved in methylhistidine metabolism. 3-Methylhistidine has been found to be associated with several diseases such as diabetes mellitus type 2, eosinophilic esophagitis, and kidney disease. The normal concentration of 3-methylhistidine in the urine of healthy adult humans has been detected and quantified in a range of 3.63–69.27 micromoles per millimole (umol/mmol) of creatinine, with most studies reporting the average urinary concentration between 15–20 umol/mmol of creatinine. The average concentration of 3-methylhistidine in human blood plasma has been detected and quantified at 2.85 micromolar (uM) with a range of 0.0–5.9 uM. As a general rule, urinary 1MH is associated with white meat intake (p< 0.001), whereas urinary 3MH is associated with red meat intake (p< 0.001) (PMID: 34091671). 3-Methyl-L-histidine is a biomarker for meat consumption, especially chicken. It is also a biomarker for the consumption of soy products.
L-3-Methylhistidine
3-Methyl-L-histidine is a biomarker for meat consumption, especially chicken. It is also a biomarker for the consumption of soy products.
3-Methyl-L-histidine
A L-histidine derivative that is L-histidine substituted by a methyl group at position 3 on the imidazole ring. 3-Methylhistidine is a product of peptide bond synthesis and methylation of actin and myosin. The measurement of 3-Methylhistidine provides an index of the rate of muscle protein breakdown. [HMDB]. 3-Methylhistidine is a biomarker for meat consumption, especially chicken. It is also a biomarker for the consumption of soy products. 3-Methyl-L-histidine is a biomarker for meat consumption, especially chicken. It is also a biomarker for the consumption of soy products.
