Imidazolepyruvic acid

Histidine, histidinol, histamine, urocanic acid, and imidazole-pyruvic, -acetic, and -lactic acids were recovered from rumen fluid and separated on an aminopropyl column (Jl = 220 nm). Elution was complete in 25 min using a 21/79 water (67 mM K2HPO4 at pH 6.45)7(90/10 acetonitrile/water) mobile phase [1430]. Excellent resolution was achieved and peak shapes were excellent except for a very broad imidazolepyruvic acid peak. Decreasing pH increased retention for the analytes. The authors also noted that frequent rinsing of the system with phosphate buffer solution only was needed. A linear range of 1-500 pM along with detection limits of 0.8-5 pM (analyte dependent) were reported. 

The biological lability of the a-amino group of histidine has been shown in various ways. It is not nutritionally essential that histidine be fed intact. In the rat imidazolelactic acid - - and imidazolepyruvic acid - can be substituted for it. n-Histidine can be converted to form the L-isomer. ... 

His, histidine IpyA, imidazolepyruvic acid UroA, urocanic acid Figlu, formiminogluta- ... 

Figlu, formiminoglutamic acid IpyA, imidazolepyruvic acid UroA, urocanic acid. L-histidine monohydrochloride is dissolved in water and given orally after an overnight fast. 350 mg of urocanic acid in a 1 mM solution of NaOH at pH 7.0 was injected slowly i.v. after an overnight fast. The plasma and urine samples should be frozen immediately after collection in order to prevent the decomposition of histidine metabolites. 

The histidinemic urine is sometimes only weakly positive or negative on ferric chloride testing, which reflects either the instability of imidazole-pyruvic acid, the relation of its excretion to protein intake, immaturity of histidine transaminase, or a combination of these factors. Even after histidine loading, histidinemic neonates excrete much smaller quantities of imi-dazolepyruvic acid than do older children. In patients with urocanase deficiency, the levels of blood histidine and urine imidazolepyruvic acid are normal or slightly elevated. Therefore, it is necessary to do a quantitative analysis of blood histidine and urine ferric chloride test in order to overlook the patients with this condition. 

Histidinaemia Histidine Imidazolepyruvic acid Imidazoleacetic add Imidazolelactic add Histidine ammonia-lyase (EC 4.3.1.3) 16.5... 

Because transamination reactions are reversible, it is theoretically possible for all amino acids to be synthesized by transamination. However, experimental evidence indicates that there is no net synthesis of an amino acid if its a-keto acid precursor is not independently synthesized by the organism. For example, alanine, aspartate, and glutamate are nonessential for animals because their a-keto acid precursors (i.e., pyruvate, oxaloacetate, and a-ketoglutarate) are readily available metabolic intermediates. Because the reaction pathways for synthesizing molecules such as phenylpyruvate, a-keto-/Thydroxybutyrate, and imidazolepyruvate do not occur in animal cells, phenylalanine, threonine, and histidine must be provided in the diet. (Reaction pathways that synthesize amino acids from metabolic intermediates, not only by transamination, are referred to as de novo pathways.)... 

Histidine ammonia lyase (histidase) (EC 4.3.1.3). Failure to form urocanic acid from histidine. Histidine elevated in blood and cerebrospinal fluid. Increased urinary histidine, imidazolepyruvate, imidazolelactate and imidazoleacetate. Formiminoglutamate not excreted after histidine load. Usually benign. Mental retardation rare. 

Blue-green Phenylpyruvic acid Imidazolepyruvic add Catecholamines Xanthurenic add Classical PKU Histidinemia Pheochromocytoma Xanthurenic aciduria (B6 defj... 

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