Histamine histidine

Annular tautomerism of azoles and benzazoles [the nonaromatic tautomers of imidazole 17, 2H and 4(5)H have been calculated at the MP2/6-31G level to be about 15 kcal mol less stable than the IH tautomer (95JOC2865)]. We present here the case of 4(5)-substituted imidazoles, different from the histamine, histidine, and derivatives already discussed. By analogy with these histamines, 4-methylimidazole 17a is often named distal [N(t)H] and 5-methylimidazole 17b, proximal [N(7t)H] (Scheme 9). 

Note o-Phthaldehyde in the presence of mercaptoethanol or cysteine has already been discussed as a reagent [4]. The present monograph describes the use of o-phthal-aldehyde in the presence of sulfuric add. There are, in addition, a number of applications, which have been described, employing o-phthalaldehyde without any additives e. g. for the detection of primary arylamines, histamine, histidine and histidylpeptides [5-71. 

Hosli, L. Haas, H. L. (1971). Effects of histamine, histidine and imidazole acetic acid on neurones of the medulla oblongata of the cat. Experientia 27, 1311-12. 

Orr, E. Quay, W. B. (1975). Hypothalamic 24-hour rhythms in histamine, histidine, decarboxylase and histamine-N-methyltransferase. Endocrinology 96, 941-5. 

Granerus, G. (1968). Effects of oral histamine, histidine, and diet on urinary excretion of histamine, methylhistamine, and l-methyl-4-imidazoleacetic acid in man, Scand. J. Clin. Lab. Invest., 10, suppl., 49. 

The peak of histidine decarboxylase activity in foetal rat liver coincides. approximately with that of haemopoietic activity . Subsequently, the bone marrow of the adult rat was found to contain a specific histidine decarboxylase Table 4.4), thus supporting the possibility of a connection between haemopoiesis and the formation of histamine . Histidine decarboxylase also occurs in the bone marrow of the guinea-pig this enzyme activity, which was shown to be related to the number of basophils, does not, however, support a relationship between histidine decarboxylase activity and growth, since the basophils in the buffy layer of guinea-pig blood have also a considerable histamine-forming capacity, but contain no cells in mitosis . ... 

The imidazole nucleus (Figure 2.7) is supplied during alkaloid biosynthesis by L-histamine. Typical alkaloids with the imidazole nucleus include histamine, histidine, procarpine, and pilosine. They are found as basic alkaloids in two principal families, Cactaceae and Rutaceae. 

An imidazole ring is a structural unit in two biologically important compounds, histidine and histamine. Histidine is one of the amino acid building blocks of proteins and is directly involved in key proton-transfer processes. The drop in blood pressure associated with shock is a result of the formation of histamine, which stimulates the dilation of blood vessels. 

The decarboxylation of amino acids (name in brackets) leads to the biogenic amines phenyl-ethylamine (phenylalanine), tyramine (tyrosine), tryptamine (tryptophan), histamine (histidine), putrescine (ornithine) and cadaverine (lysine). The content of these compounds in some types of cheese is presented in Table 10.34. These values can fluctuate greatly depending on the degree of ripening. On average, 350-500 pmol per person per day are consumed. Apart from cheese. 

Histamine Histidine Local tissue hormone, reduces blood pressure, effect on gastric Juice secretion, participation in anaphylactic shock and allergic reactions... 

Detection of Histamine.—(1) Diazo Reaction (Pauly).— Freshly prepared diazo reagent is added to a dilute alkaline solution of the amine. A deep red indicates histamine, histidine, and other iminazole derivatives. On acidification, the colour changes to orange. Tyrosine and other y-hydroxy compounds give similar colours. 

Imaging/Labeling Applications Cellulose cyclodextrin-based polyrotaxanes histamine/ histidine lysozymes nucleic acids polyamines proteins " poly(dimethylsiloxane) (PDMS) oligomers ... 

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