Urea Cycle

The urea cycle, also referred to as the ornithine or Krebs-Henseleit cycle, is essential to the removal of excess nitrogen as well as to the detoxification of ammonia.  This pathway consists of 5 enzymatic reactions, with the first taking place in the mitochondrial matrix and the ensuing in the cytosol.  Key intermediates of the cytosolic reactions are the amino acids -- ornithine, citrulline, argininosuccinic acid, and arginine.  Enzymatic deficiencies cause urea cycle disorders (UCDs; e.g., ornithine transcarbamylase deficiency, argininosuccinate synthetase deficiency), with the intermediates serving as potential biomarkers for MS-based screening exercises.  CIL is pleased to offer all four of these compounds in their stable isotope-labeled and/or unlabeled form as neat materials for use in exploratory or translational research applications.

For additional information, please see our Stable Isotope Standards for Mass Spectrometry catalog.