During exercise, ammonia levels are related to the appearance of both central and peripheral fatigue. Therefore, controlling the increase in ammonia levels is an important strategy in ameliorating the metabolic response to exercise and in improving athletic performance. Free amino acids can be used as substrates for ATP synthesis that produces ammonia as a side product. Keto analogues act in an...

1. Increases in the concentrations of lactic acid and pyruvic acid in rat brain during acute dieldrin poisoning are associated with hyperactivity of the brain, whereas an increase in the cerebral alanine concentration occurs before the convulsions. Throughout the dieldrin-induced seizure pattern, fluctuations in the concentration of brain ammonia are out of phase with the actual convulsions. 2....

The performance of Co3Mo3N, Co3Mo3C, and Co6Mo6C for ammonia synthesis has been compared. In contrast to Co3Mo3N, which is active at 400 °C, a reaction temperature of 500 °C, which was preceded by an induction period, was necessary for the establishment of steady state activity for Co3Mo3C. Co6Mo6C was found to be inactive under the conditions tested. During the induction period, nitridation of...

Mutants of Escherichia coli K12 defective in the nirB gene lack NADH-dependent nitrite reductase activity and reduce nitrite slowly during anaerobic growth. With one exception these mutants require cysteine for growth. Cytochrome C552 synthesis and the assimilation of ammonia are unaffected by the nirB mutation. The defective gene is located between the crp and aroB genes at minute 73 on the E...

14C and 15N isotopes of urea were infused intravenously into rabbits for 6-8 h in order to measure urea synthesis and the extent of degradation in the digestive tract. The results indicate that 0.62 of the urea flux was excreted in the urine and that re-incorporation of urea-N following hydrolysis in the gut represented 0.3 of the urea synthesis rate. Sampling of metabolites from the caecum by ...

Carbamoyl phosphate synthetase (CPS) from Escherichia coli consists of a small subunit (approximately 42 kDa) and a large subunit (approximately 118 kDa) and catalyzes the biosynthesis of carbamoyl phosphate from MgATP, bicarbonate, and glutamine. The enzyme is able to utilize external ammonia as an alternative nitrogen source when glutamine is absent. CPS contains an internal molecular tunnel,...

well-known effects on lowering blood ammonia concentrations by increasing urea synthesis [1]. Moreover, accumulating evidence suggests that L-ornithine aspartate restores muscle protein synthesis, an effect which can be exploited in patients suffering from cancer or HIV infections [2]. Other studies showed significant improvements of clinical values and liver function in patients undergoing rad...

Sprinson and Rittenberg,’ in their studies of the effects of diet on the retention of ammonia, were led to conclude that ammonia is extensively utilized for protein synthesis only when there is a deficiency of dietary amino acids. For some time this laboratory has been engaged in a study of the influence of glucose on the metabolism of amino acids and proteins. The results so far obtained indic...

Commercial design of a sustainable route for on-site production of ammonia represents a potential economic and environmental breakthrough. In an analogous process to the naturally occurring enzymatic mechanism, synthesis of ammonia could be achieved in an electrochemical cell, in which electricity would be used to reduce atmospheric nitrogen and water into ammonia at ambient conditions. To date...