Search results
Results From The WOW.Com Content Network
The histidine amino acid is a precursor for histamine, an amine produced in the body necessary for inflammation. [25] The enzyme histidine ammonia-lyase converts histidine into ammonia and urocanic acid. A deficiency in this enzyme is present in the rare metabolic disorder histidinemia, producing urocanic aciduria as a key diagnostic finding.
Histidinemia is a rare autosomal recessive metabolic disorder caused by a deficiency of the enzyme histidase. Histidase is needed for the metabolism of the amino acid histidine . [ 1 ] Although originally thought to be linked to multiple developmental disorders histidinemia is now accepted as a relatively benign disorder, [ 2 ] leading to a ...
The use of acidosis for a low pH creates an ambiguity in its meaning. The difference is important where a patient has factors causing both acidosis and alkalosis, wherein the relative severity of both determines whether the result is a high, low, or normal pH. [citation needed] Alkalemia occurs at a pH over 7.45.
The triad of cytomegalovirus protease [b] uses histidine as both the acid and base triad members. Removing the acid histidine results in only a 10-fold activity loss (compared to >10,000-fold when aspartate is removed from chymotrypsin). This triad has been interpreted as a possible way of generating a less active enzyme to control cleavage ...
An abnormally low pH in the extracellular fluid is called an acidemia and an abnormally high pH is called an alkalemia. [citation needed] Acidemia and alkalemia unambiguously refer to the actual change in the pH of the extracellular fluid (ECF). [24] Two other similar sounding terms are acidosis and alkalosis. They refer to the customary effect ...
Cystine and Histidine are very commonly involved, since they both have a pKa close to neutral pH and can therefore both accept and donate protons. Many reaction mechanisms involving acid/base catalysis assume a substantially altered pKa. This alteration of pKa is possible through the local environment of the residue [citation needed].
Histamine is derived from the decarboxylation of the amino acid histidine, a reaction catalyzed by the enzyme L-histidine decarboxylase. It is a hydrophilic vasoactive amine . Conversion of histidine to histamine by histidine decarboxylase
Histidine and aspartate phosphorylation occurs in prokaryotes as part of two-component signaling and in some cases in eukaryotes in some signal transduction pathways. The analysis of phosphorylated histidine using standard biochemical and mass spectrometric approaches is much more challenging than that of Ser, Thr or Tyr.