Disease relevance of OTC

• This showed ratio between toxicity levels (bacteria) (EC50=0.14 mg/l) and measured concentrations (LOD=1 microg/l) for OTC to be 140 [1].
• Out of 30 calves treated with two to four doses of OTC/LA from one to four weeks after vaccination, 29 remained negative for A. centrale and reacted to challenge infection with average maximum parasitemias of 6.9-7.8% [2].
• Calves vaccinated with Anaplasma centrale were treated with 20 mg/kg of long-acting oxytetracycline (OTC/LA) before or simultaneously with vaccination or up to seven months later [2].
• The essential sulfhydryl group of the ornithine transcarbamylases (ornithine carbamoyltransferase, 2.1.3.3) from bovine liver and Streptococcus faecalis reacts preferentially with 2-chloromercuri-4-nitrophenol [3].
• The peptides produced by cleavage of the S-cyano derivatives of the ornithine transcarbamylases (ornithine carbamoyltransferase, 2.1.3.3) from bovine liver, Streptococcus faecalis ATCC 11,420, and Streptococcus faecium ATCC 8043 have been isolated and aligned [4].

High impact information on OTC

• ATP and a number of purine nucleotides, particularly epsilon-ATP, stimulate the inactivation of OTC by broken lysosomes [5].
• Carbamoyl phosphate protects OTC against proteolytic attack by elastase or by broken lysosomes [5].
• Ornithine transcarbamylase (OTC) is very stable in rat liver homogenates, or mitochondria [5].
• Ornithine transcarbamylase (OTC) in white blood cells [6].
• All these cell lines demonstrated no OTC activity [6].

Chemical compound and disease context of OTC

• Only ornithine carbamoyltransferase and iditol (sorbitol) dehydrogenase could be used to separate healthy cows from those with severe ketosis [7].

Biological context of OTC

• In contrast, the OCT activities were fairly constant for each tissue as a function of gestational age [8].

Anatomical context of OTC

• However, pure OTC from rat or beef liver is inactivated by broken lysosomes [5].
• The average OTC activity of granulocytes was 1.0 nmoles/mg/hr, whereas that of mononuclear cells was 0.4 mmoles/mg/hr [6].
• Lymphoid cell lines were established from three normal subjects and an OTC-deficient infant [6].
• These results show that when OTC/LA is administered following anti-babesial vaccination, parasitaemia and red blood cell destruction are significantly reduced without, however, inhibiting the development of immunity [9].
• Ornithine carbamoyltransferase (OCT), a urea cycle enzyme, is located almost exclusively in liver mitochondria [10].

Associations of OTC with chemical compounds

• Thus, environmental factors, e.g., ATP and carbamoyl phosphate, appear to influence OTC stability to proteases [5].
• On the contrary, the apparent Km's of human liver OTC were 0.6 mM for ornithine and 0.12 mM for carbamyl phosphate [6].
• Since the inactivation is prevented by leupeptin, antipain and L-(tosylamido-2-phenyl)ethylchloromethyl ketone, the proteolytic susceptibility of OTC to lysosomes could be due to thiol endopeptidase(s) [11].
• The renal OTC clearance, the renal creatinine clearance, the urinary flow, and the interrelationships of these were determined on the basis of urine and plasma data [12].
• Three groups of 10 calves each were treated with two, three or four doses of 20 mg kg-1 long-acting oxytetracycline (OTC/LA) at six- to seven-day intervals starting from day 6 after vaccination [9].

Other interactions of OTC

• Liver biopsies were obtained on d -28, -14, 1, 28, and 56 relative to calving, and the abundances of AS, OTC, PC, PEPCK, and 18S mRNA were determined by Northern blot analysis of total RNA [13].
• The enzymes measured were: carbamyl phosphate synthetase (CPS), ornithine transcarbamylase (OTC), argininosuccinate synthetase (AS), argininosuccinase (AL) and arginase (A) [14].

Analytical, diagnostic and therapeutic context of OTC

• Thirty calves treated with 2-4 doses of OTC/LA about six months after vaccination showed no or only a few parasites upon challenge [2].
• The renal OTC elimination is the net result of mainly glomerular filtration, partly tubular secretion, minus reabsorption in the urogenital tract [12].
• A sensitive enzyme-linked immunosorbent assay of serum ornithine carbamoyltransferase [10].

References