Disposal of nitrogen

Summary of Chapter 19 Amino Acids Disposal of Nitrogen... 

UNIT IV Nitrogen Metabolism Chapter 19 Amino Acids Disposal of Nitrogen 243 Chapter 20 Amino Acid Degradation and Synthesis 259 Chapter 21 Conversion of Amino Acids to Specialized Products 275 Chapter 22 Nucleotide Metabolism 289... 

Nitrogen oxide production and reduction Relevant to the production and disposal of nitrogen oxides as signaling molecules and biological responses to environmental nitrogen oxides. 

Several standard and nonstandard amino acids act as metabolic intermediates. For example, arginine, citrulline, and ornithine (Figure 5.6) are components of the urea cycle (Chapter 15). The synthesis of urea, a molecule formed in vertebrate livers, is the principal mechanism for the disposal of nitrogenous waste. 

Thus, we see that transaminases perform two vital functions in amino add metabolism. By taking part in the biosynthesis of nonessential amino acids, they provide a means to help readjust the relative proportions of amino acids to meet the particular needs of the body. This is a vital function because most of our diets do not contain amino acids in the exact proportions the body requires. Also, as we noted in Section 14.9, transamination reactions allow the nitrogen atoms of all amino acids to be transferred to a-keto acids to form glutamate and aspartate when disposal of nitrogen is necessary. 

Transaminases are used in the biosynthesis of amino acids and in the transfer of nitrogen atoms from amino acids when the disposal of nitrogen is necessary. 

Disposal of nitrogen trifluoride by exhausting it into water is impractical because it hydrolyzes very slowly and its solubility in water is very low. Venting into the atmosphere also should be avoided. Since nitrogen trifluoride is approximately three times as dense as air, it can settle out and cause local areas of high NF3 concentration [1]. 

Disposal of nitrogen trifluoride can be accomplished by combustion with a fuel such as activated charcoal, hydrocarbons, or metals at elevated temperatures. Reactions with activated charcoal produce nitrogen and carbon tetrafluo-ride. Carbon bed temperatures must be maintained above 1202°F (650°C) to assure reaction and to prevent gas adsorption. Similarly, nitrogen trifluoride streams can be scrubbed by introducing the gas through a packed bed of metals or metal oxides maintained at above 1000°F (538°C), followed by caustic scrubbing. 

Should it become necessary to dispose of nitrogen dioxide from a leaking cylinder, the following procedure may be used. Move the cylinder to a hood or safe out-of-doors area. 

At the other end, it is increasingly difficult to dispose of nitrogen accumulation resulting from highly concentrated meat production large beef feedlots, piggeries, and broiler houses now contain many thousands of animals. And animals use nitrogen... 

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