Amino acids and ammonia

K2. Kirk, E., Amino acid and ammonia metabolism in liver disease. Acta Med. Scand. Suppl. 78 (1936). 

Heterocyclic aroma compounds found in meat primarily arise from interactions between mono- and dicarbonyl compounds, H2S and ammonia. The carbonyl compounds are derived from the Maillard reaction, including Strecker degradation of amino acids, oxidation of lipids and aldolization reactions. H2S is produced by thermal degradation of sulfur amino acids and ammonia by amino acid pyrolysis. 

Table II. Effect of Amino Acids and Ammonia on Growth of Strain Ml, Methanobacterium ruminantium...

The numerous theories advanced on the origin and structure of complex organic nitrogen components of soils fall into two classes (1) complexes formed by reactions of phenol compounds with proteins, amino acids, and ammonia and (2) complexes formed by reactions of carbohydrates with... 

Benjamin AM, Quastel JH (1975) Metabolism of amino acids and ammonia in rat brain cortex slices in vitro a possible role of ammonia in brain function. J Neurochem 25 197-206. 

A great deal of work has been devoted to recognition of the structure of melanoidins. A wide variety of methods has been employed for this purpose. First, melanoidin shows a hyperfine structure in the e.s.r. spectrum and that means that stable free-radicals are present in caramel. Amino acids and ammonia were also detected in nondialyzable melanoidin after acid hydrol-ysis, indicating that amides are present in melanoidin. 

During decomposition most of the nitrogen is immobilized initially, at least, in microbial cells, which in turn are broken down. In the process, a considerable portion of the nitrogen reacts with phenols, quinones, and other ring compounds derived from lignin, or synthesized by microorganisms, to form humic substances, some of which are heterocyclic. Amino acids and ammonia are subject to such chemical reactions, that may be catalyzed by microbial enzymes. In soils with 2 1 clay minerals any ammonia that is formed is also subject to fixation in the clay lattice (see Chapter 8 and 11). 

Olsen KH (1986a) Emission rate of amino acids and ammonia and their role in olfactory preference behaviour of juvenile Arctic charr, Salvelinus alpinus (L.). J Fish Biol 28 255-265... 

The transformation of curd into cheese is accomplished by the influence of various enzymes (i) galactase, a special trypsin, secreted by the mammary glamd simultaneously with the milk, an active substance of which we have previously had occasion to speak (2) pepsin, which is always found associated with rermet and which some writers even confound with it (3) various tryptases, or caseases, secreted by molds, bacteria, yeasts, etc., which develop on the surface or in the interior of the mass. To these enzymes, which dissolve casein and bring it to the simpler state of peptones, amino-acids, and ammonia, it is proper to add (4) amidases, that produce the formation of volatile acids (5) lactase and lactacidase, enzymes secreted by lactic bacilli, and which transform lactose into glucose and then into lactic add (6) lipases, which apparently decompose a part of the fatty material (7) finally oxidases, which bum the organic wastes, especially the adds. 

Deferrari G. (1981). Brain metabolism of amino acids and ammonia in patients with chronic renal insufficiency. Kidney Int 20, 505. 

The organism can also be subjected to experimental intervention such as, for example, the removal of an organ. The normal mammal converts the nitrogen of amino acids into urea, but this is no longer the case when the organism is deprived of the liver. The amino acids and ammonia accumulate in the blood. Alternatively, the urea formed when the liver is present is eliminated by the kidneys and it is the urea which would accumulate in the blood if the kidneys were removed. 

These are the substances in blood, other than proteins, which contain nitrogen. They include urea, creatinine, uric acid, amino acids and ammonia. The non-protein nitrogen fraction can be determined by a micro-Kjeldahl method, followed by Nesslerization. In most laboratories, however, blood urea is determined and the other non-protein nitrogen compounds are measured only where clinically indicated, e.g. uric acid. 

MacLean, D.A., Spriet, L.L., Hultman, E., and Graham, T.E., Plasma and muscle amino acid and ammonia responses during prolonged exercise in humans, J Appl Physiol, 70, 2095, 1991. 

Bergman, E.N., C.F. Kaufman, J.E. Wolff and H.H. Williams, 1974. Renal metabolism of amino-acids and ammonia in fed and fasted pregnant sheep. Am. J. Physiol. 226, 833-837. 

The crude protein includes free amino acids and ammonia, polypeptides of various chainlength, as well as vitamins, enzymes and other biocatalysts. Utilization includes ... 

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