1-Methyl histidine

Lysine 3-Methyl-histidine Tryptophan Carnosine Anserine Homocarnosine... 

Abbreviations LSK = leucosulfakinin Nle - norleucine 3MeHis - 3 methyl histidine. Average of ... 

Fig.5.2. Post-translational modification of histidine residues in skeletal muscle proteins, and the release of 3-methyl histidine after proteolysis.

Fig. 2. The elution pattern of a standard mixture of OPA-derivatized primary amines, separated on a 5 (Jim Nucleosil C-18 column (200 X 4.6 mm id). The flow-rate was 1 mL/min employing the indicated gradient of metlianol and Na phosphate buffer (50 mA4, pH 5.25). Each peak represents 39 pmol except for those indicated below. 1, glutathione 2, cysteic acid 3, O-phosphoserine (19.5 pmol) 4, cysteine sulfinic acid 5, aspartic acid 6, asparagine (19.5 pmol) 7, glutamic acid 8, histidine 9, serine 10, glutamine 11, 3-methyl-histidine 12, a-aminoadipic acid (9.8 pmol) 13, citrulline (9.8 pmol) 14, carnosine 15, threonine,glycine 16, O-phosphoethanolamine 17, taurine (19.5 pmol) 18, p-alanine (19.5 pmol) 19, tyrosine 20, alanine 21, a-aminoisobutyric acid 22, aminoisobutyric acid 23, y-amino-ii-butyric acid 24, p-amino-u-butyric acid 25, a-amino-butyric acid 26, histamine 27, cystathione (19.5 pmol) 28, methionine 29, valine 30, phenylalanine 31, isoleucine 32, leucine 33, 5-hydroxytryptamine (5-H i ) 34, lysine. The chromatographic system consisted of a Varian LC 5000 chromatograph and a Schoeffel FS 970 fluorimeter.

Poly-(l-benzyl)-L-histidine is a very interesting polymer also for other reasons. First, the benzyl substitution on the imidazole ring can occur in two different places, with possible effects on the geometry of the side-chains. (In this connection, it should be interesting to study the conformational properties of poly-1-methyl-, and poly-3-methyl-histidine). Second, the polymer assumes a new conformation specifically induced by the presence of perchlorate ions [68—70]. The CD pattern of this form is characterized by a very strong negative band below 200 nm. We do not know at the present time to what conformation does correspond this CD spectrum. 

R = ch3 N(n)-Methyl-histidin [5-(2-Amino-2-carboxy-ethyt)-1-melhyl-imidazol 75%... 

The enzyme contains five posttranslationally modified amino acids near the active site N-methyl-histidine, 5-methylarginine, 2-methylglutamine, 2-methyl-cysteine, and thioglycine in a thiopeptide bond. The latter may be the site of radical formation.4583 13... 

The metal ion-promoted hydrolysis of a number of bidentate esters such as methyl 2,3-diaminopropionate (8), methyl histidinate (9), methyl cysteinate (10) and the ethyl ester of ethylenediaminemonoacetate (11) have been studied. The first three esters give very thermodynamically stable metal complexes in solution with pendant ester functions.64"71 Typical kinetic data for these systems are given in Tables 9 and 10. 

In a series of elegant studies, Miller and colleagues demonstrated that small peptides containing modified histidine residues (re-methyl-histidine) were effective catalysts for enantioselective acylation and phosphorylation reactions [12, 13]. As peptides in this family are able to transfer stereochemical information, these catalysts were also tested to carry out site- and regio-selective reactions, which take place against kinetic expectations. The screening of a small library (36 members)... 

AFOO-Phosphorylhistidine AT -f Methyl)histidine 4-(iodo)histidine 8a-(histidyl)flavin ADP-ribosylation... 

Anserine P-alanyl-N -methyl-histidine Vertebrate skeletal muscles, heart, brain 1929... 

Ophidine p-alanyl-N -methyl-histidine Snake, dolphin and whale musculature 1939... 

Homoanserine y-aminobutyryl-N -methyl- histidine Cardiac muscle and brain 1969... 

N-acety 1-methyl-histidine N-acetyl-N -methyl-histidine Cardiac muscle and brain 1988... 

N -Acetyl-anserine N-acetyl-p-alanyl- N -methyl-histidine Heart muscle 1988... 

Homocamosinosis. This disease is accompanied with pronounced increase of homocamosine level in brain and cerebrospinal liquid as well as camosine in urea with simultaneous disability to metabolize anserine into N -methyl-histidine (see [107]). Normal level of camosine and homocamosine is exceeded 20 and more times and this is accompanied with apparent neurological deficit. At the same time, relatives of the patients can get similar shifts in dipeptides metabolism with no neurological symptomatic. The cause of such disorder of metabolism in patients with homocamosinosis is that camosine splitting enzyme, carnosinase is mainly present in the inactive form [109,110],... 

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) ... 

Amino acid esters may coordinate as a monodentate (amino N) or as a bidentate (N,0) ligand. In the latter case (17) significant polarization of the ester bond results which is of likely importance in the reaction mechanism (Scheme 6). Alternatively, hydroxide attack at the metal centre may occur (equation 15). Hydroxide ion rather than water is the predominant nucleophile, even at pH 5. Direct evidence for metal-ester bond formation comes from isolated Co" complexes which contain such a bond. Rate enhancements, compared to the free amino acids, are often of the order of lO -lO . For methyl histidinate, however, rate enhancement by Cu" is only of the order of265 this is ascribed to there being no Cu-ester bond formation. The order of decreasing reactivity in this study was established as being CuE " > Ni > CuE > NiE " > EH" > CuEA > CuEOH > NiEA > E, where E is L-HisOMe and A is L-HisO . The relative effectiveness of protons and metal ions as catalysts has been discussed by Martin. ... 

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