Ornithine carbamoyltransferase has been purified from the liver of the loggerhead turtle Caretta caretta by a single-step procedure using chromatography on an affinity column to which the transition-state analogue, delta-N-(phosphonoacetyl)-L-ornithine (delta-PALO), was covalently bound. The procedure employed yielded an enzyme which was purified 373-fold and was judged to be homogeneous by non...

1. Urea cycle enzymes and ornithine ketoacid transaminase were extracted from rat liver using various buffer systems and different procedures for the mechanical disintegration of the cells. Of the buffers tested, phosphate and glutathipne gave optimal results, whereas significant differences were found when other extracting media were used: activities of ornithine ketoacid transaminase and orni...

were not secondary to stimulation of steroidogenesis, since hydrocortisone had no effect on adrenal ornithine decarboxylase although it did stimulate activity of the enzyme in the liver and kidney. ACTH, given subcutaneously to hypophysectomized rats, induced striking increases in adrenal cyclic AMP levels within 15-30 min with a fall towards the base line in 1 h. Increases in ornithine decarbo...

Ornithine decarboxylase and arginine decarboxylase activities were measured in roots and buds of tomato (Lycopersicon esculentum Mill. cv. Pearson ms-35) and potato (Solanum tuberosum cv. Desire) plants. In both tomato and potato, the activity of ornithine decarboxylase was the highest at the root tip, decreasing proximally. The same was true for potato buds. In vegetative buds of tomato, the h...

The induction of ornithine decarboxylase by normal rat urine in bladder cancer cell cultures was tested in view of recent observations that urine acts as a tumor promoter. Addition of urine up to 15% in final concentration to culture medium resulted in a 10-fold increase in ornithine decarboxylase activity over the control. The stimulatory factor(s) contained in urine appears heat stable and ma...

The effect of oral L-ornithine hydrochloride (0.1 g/kg BW) on energy expenditure during a rest period from 120 to 180 min after resistance exercise was evaluated by indirect calorimetry. Healthy male subjects who have no habit of resistance training underwent resistance exercise (chest press, lat pulldown, leg press, shoulder press, leg extension, and leg curl), with 3 sets of each exercise and...

In eukaryotic cells, the non-proteinogenic amino acid ornithine is the precursor of arginine and polyamines (PAs). The final step of ornithine biosynthesis occurs in plants via a cyclic pathway catalyzed by N(2)-acetylornithine:N-acetylglutamate acetyltransferase (NAOGAcT). An alternative route for ornithine formation, the linear pathway, has been reported for enteric bacteria and a few other o...

We have previously shown that arginine deficiency is exacerbated by the removal of dietary proline in orally, but not parenterally, fed piglets. Therefore, we hypothesized that the net interconversions of proline, ornithine, and arginine primarily occur in the small intestine of neonatal piglets. Ten intragastrically fed piglets received either intraportal (IP) or intragastric (IG) primed, cons...