Search results
Results From The WOW.Com Content Network
A typical characteristic of histidinemia is an increase in the blood histidine levels from normal levels (70–120 μM) to an elevated level (290–1420 μM). [3] Further testing includes: observing histidine as well as imidazolepyruvic acid metabolites in the urine. However, neonatal urine testing has been discontinued in most places, with the ...
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 (μmol/mmol) of creatinine, with most studies reporting the average urinary concentration between 15–20 μmol/mmol of creatinine. [1]
In urocanic aciduria, increased urocanic acid in the urine indicates a deficiency of the enzyme urocanase. [citation needed] With normal to only slightly elevated levels of histidine present in the liver during urocanic aciduria, the only true metabolic indicator of the disorder can be found in the urine. [2]
Urocanic acid is found predominantly in the stratum corneum of the skin and it is likely that most of it is derived from filaggrin catabolism (a histidine-rich protein). When exposed to UVB irradiation, trans-urocanic acid is converted in vitro and in vivo to cis -urocanic acid (cis-UCA). [ 4 ]
Urocanase [1] (also known as imidazolonepropionate hydrolase or urocanate hydratase) is the enzyme (EC 4.2.1.49 4.2.1.49) that catalyzes the second step in the degradation of histidine, the hydration of urocanate into imidazolonepropionate. Urocanase is coded for by the UROC1 gene, located on the 3rd chromosome in humans. [2]
Regina Kapeller-Adler, born Regina Kapeller, (28 June 1900 – 31 July 1991) was an Austrian biochemist who, in 1934, devised an innovative test for early pregnancy based on the detection of histidine in urine.
Histidine ball and stick model spinning. Histidine (symbol His or H) [2] is an essential amino acid that is used in the biosynthesis of proteins.It contains an α-amino group (which is in the protonated –NH 3 + form under biological conditions), a carboxylic acid group (which is in the deprotonated –COO − form under biological conditions), and an imidazole side chain (which is partially ...
The molecular mechanism behind this effect is the steric organization of the globin chain; a histidine residue, located adjacent to the heme group, becomes positively charged under acidic conditions (which are caused by dissolved CO 2 in working muscles, etc.), releasing oxygen from the heme group. [15]