N-Methylhistidine

An ever-increasing number of amino acid derivatives is found to occur naturally in proteins. These include s-N-methyllysines, e-N-acetyl-lysine, a-N-acetyl derivatives of various residues, N-methylhistidines, N-phosphohistidines, N-methylarginines, phosphoserine, phospho-threonine, hydroxyproline, hydroxyJysine, trimethylhydroxylysine, tyrosine sulfate, iodotyrosines, carbohydrate moieties and coenzymes... 

Solomon, L. R. Rubenstein, P. A. (1987). Studies on the role of actin s N -methylhistidine using oligodeoxynucleotide-directed site-specific mutagenesis. J. Biol. Chem. 262, 11382-11388. 

Protein ( histidine ) Methyltransferase. An enzyme which methylates histidine in proteins to give primarily 3-methylhistidine residues has been observed in myofibrillar protein and in the sarcoplasmic fraction of muscle homogenates (218). S-Adenosyl-L-methionine serves as the methyl donor for the enzyme. The enzyme has not been solubilized and purified. Very little is known about the substrate specificity of protein-(histidine) methyltransferase. Actins from a wide variety of species consistently contain one 3-N-methylhistidine residue per molecule (191, 219). It appears that myosin from white muscle contains two residues of 3-N-methylhistidine (one residue per heavy chain), whereas myosin from red muscle contains no 3-N-methylhistidine (220). The amino acid sequence around the methylated residue of rabbit skeletal muscle is (221) ... 

The amino acid sequence in rabbit cardiac muscle myosin is homologous with that around the 3-N-methylhistidine residue in rabbit skeletal muscle myosin, yet it does not contain a 3-N-methylhistidine residue. 

L-N-Methylhistidine (20 R = Me) or its ethyl counterpart (20 R = Et) can be prepared by treating carhoxy-methylhistidine (18) with NN -carbonyldi-imidazole to give the imidazo[l,5-c]pyrimidine (19) this, upon alkylation (with RI) followed by hydrolysis (with 6M-HC1) gives the N-alkyl-histidine (20 R = Me or Et). 

Hayashi, K., Tomita, Y., Maeda, Y., Shimagawa, Y., Inoue, K. Hashizume, T. (1985). The rate of degradation of myofibrillar proteins of skeletal muscle in broiler and layer chickens estimated by N-methylhistidine in excreta. Br.. Nutr., 54, 157-63. 

In addition to kinetic resolution processes, the previously described peptide-catalysed acylation reaction of alcohols can be applied to desymmetrisation of meso compounds. In 2005, Miller and coworkers published the desymmetrisation of prochiral glycerol derivatives via enantioselective acylation of one primaiy alcohol function. A (3-tum histidine-based pentapeptide was identified as the most promising catalyst from a peptide libraiy and afforded the monoacylated product with up to 97% enantiomeric excess. One year later Miller and Hansen successfully demonstrated the desymmetrisation of a meso bis-phenol compound, which was found to be challenging because of the large distance between the two OH groups as well as between the desired site of functionalisation and the prochiral stereogenic centre of the substrate. The nucleophilic N-methylhistidine containing peptide 9 was identified as a powerful tool for monoacylation via extensive libraiy... 

Glass Capillary Gas Chromatographic Determination of N-Methylhistidine in Urine... 

Picomole Assay for N-Methylhistidine by Gas Chromatography-Mass Spectrometry... 

It is known that in fish, two less commonly occurring amino acids are major contributors to the browning reaction and to the loss of free sugar, i.e., anserine, a dipeptide, /i- a I a n y l-i-mctliyl liistidinc, and taurine, H3N+.CH2.CH2.S03 . Discoloration of fish at 0% r.h. in sunlight has been shown to be due to 1-methylhistidine without the... 

Other products from histidine include the hormonal substance histamine formed by decarboxylation, the oxidation product, imidazole acetic acid, and N - and IV -methylhistidines. Histamine plays a role in release of gastric secretions and allergic responses (Chapter 5). Drugs (antihistamines) that inhibit its release are in widespread use. The unusual amino acid diphthamide has an unknown function in pro-... 

Young, V.R. and Munro, H.N., Ntau-methylhistidine (3-methylhistidine) and muscle protein turnover an overview. Fed Proc, 3TI, 2291, 1978. 

A similar 7t-methyl histidine-based strategy was chosen by Qu et al. in their quest to develop a low molecular weight catalyst for the KR of racemic secondary alcohols [68]. Hence, after screening a series of catalysts bearing a methyl histidine moiety, N-thiobenzoyl-l-methylhistidine methyl ester 73 was found to be a particularly efficient catalyst for the KR of monoprotected cis-diols as well as terminal vicinal diols. 

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