Assay of ornithine transcarbamylase and carbamyl phosphate synthetase I in submitochondrial fractions of rat liver mitochondria shows they are located primarily in the mitochondrial matrix. Therefore during the urea cycle ornithine must pass from the cytoplasm, where it is formed, to the mitochondrial matrix, where it is carbamylated. The resulting citrulline must then pass from the matrix to t...

A 57 year old woman with post-traumatic complex partial seizures was admitted because of recurrent episodes of altered mental state over the preceding 4 years, each lasting up to 5 days. There was a history of dietary protein intolerance since childhood and two of her daughters had died in the neonatal period from unexplained encephalopathies. In hospital she developed fluctuating confusion, am...

The specific syndrome arising from an absent or low hepatic ornithine transcarbamylase activity has been termed hyperammonaemia (Russell et al., 1962; Levin and Russell, 1967; Levin, 1968). In the previous communication (Levin et al., 1969) 2 cases occurring in mother and child are described. In this article, we record an infant who during the course of an investigation for the cause of his vom...

The presequence of the ornithine transcarbamylase precursor (pOTC) was fused to green fluorescent protein (GFP), yielding pOTC-GFP and pOTCN-GFP containing the presequence plus 4 and 58 residues of mature ornithine transcarbamylase, respectively. When GFP cDNA was transfected into COS-7 cells, the cytosol and nucleus were fluorescent. On the other hand, pOTC-GFP cDNA gave strong fluorescence of...

The article reviews literature and demonstrates personal observation of a preschool patient with ornithine transcarbamylase deficiency. This disease is characterized by an excessive accumulation ammonia in the body, which leads to damage nervous system, gastrointestinal tract, impaired liver function. It has genetically determined mechanism development associated mutations OTC gene. Purpose - s...

Two crystal structures of human ornithine transcarbamylase (OTCase) complexed with the substrate carbamoyl phosphate (CP) have been solved. One structure, whose crystals were prepared by substituting N-phosphonacetyl-L-ornithine (PALO) liganded crystals with CP, has been refined at 2.4 A (1 A=0.1 nm) resolution to a crystallographic R factor of 18.4%. The second structure, whose crystals were p...