Urea amino acids

The elemental and vitamin compositions of some representative yeasts are Hsted in Table 1. The principal carbon and energy sources for yeasts are carbohydrates (usually sugars), alcohols, and organic acids, as weU as a few other specific hydrocarbons. Nitrogen is usually suppHed as ammonia, urea, amino acids or oligopeptides. The main essential mineral elements are phosphoms (suppHed as phosphoric acid), and potassium, with smaller amounts of magnesium and trace amounts of copper, zinc, and iron. These requirements are characteristic of all yeasts. The vitamin requirements, however, differ among species. Eor laboratory and many industrial cultures, a commercial yeast extract contains all the required nutrients (see also Mineral nutrients). 

Taxa and species % Urea % Amino acids % TDN excreted as DON Reference... 

Urea, % total dissolved nitrogen excreted as urea % amino acids, % total dissolved nitrogen excreted as amino acids % TDN excreted as DON, % total dissolved nitrogen excreted as DON. Note Most studies did not measure actual total dissolved nitrogen, but rather ammonia, urea, and amino acids. 

Urea + amino acid)/(ammonia + urea + amino acids). 

Bis(trimethylsilyl)acetamide (1). Mol. wt. 203.44, b.p. 71-73735 mm. Prepared in 80% yield by reaction of acetamide with trimethylchlorosilane with triethylamine as catalyst, the reagent effects trimethylsilyUuion of amides, ureas, amino acids, phenols, carboxylic acids, enols. ... 

Procedures were developed for the synthesis of new types of simple receptors based on substituted 1,8-naphthyridines. These receptors serve as carriers for the transport of biologically important organic substrates (urea, amino acids, hydroxy acids) into cells (1999JIC661, 2001T4987, 2002EJOC4063). 

Most plants can utilize directly ammonia, nitrates and a few organic compounds such as urea, amino acids and amides. In addition, nitrite is usually assimilated readily, but at soil concentrations greater than about 10—20 p.p.m. is likely to produce signs of toxicity. 

Due to the fact that the extracellular proteolytic activity of Saccharomyces is negligible, high-molecular-weight nitrogenous materials can not be utilized by the cells. Therefore the application of inorganic ammonium ions e.g. ammonium sulphate, di-ammonium hydrogenphosphate), urea, amino acids or small peptides is necessary. ... 

These early studies also contributed to an imderstanding of the site of uric acid bios mthesis and led to several hypothetical reaction schemes. In 1877 several investigators showed that although the feeding of urea, amino acids, or ammonium salts to mammals led to an increase in the excretion of urea, the feeding of these compounds to birds resulted instead in an increased excretion of uric acid. Minkowski showed in 1886 that hepatecto-mized birds did not synthesize uric acid from such precursors, and because urinary lactate was elevated in such birds, he suggested that uric acid was synthesized from lactate and ammonia. 

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