Nitrogen metabolism

Nitrogen metabolism - the sum of what is happening in the body transformation of nitrogen-containing compounds, mainly of proteins. In animals and humans nitrogen metabolism consists of three main stages: 1) hydrolytic decomposition of nitrogen in the gastrointestinal tract and absorption of products formed; 2) transformation of these products in tissues, leading to the formation of proteins (see) and other nitrogen-containing compounds; 3) the selection of the final products of nitrogen metabolism from the body. (Metabolism actually proteins and their derivatives called protein metabolism.) In the adult organism in norm the amount of protein synthesized (per day) is equal to the total amount of decaying tissue and food proteins, i.e. nitrogen balance is close to zero. This condition is called protein balance. In the state of the protein balance per day with urine and faeces in humans appears around 3.7 grams of nitrogen, which corresponds to 23 g of protein (dry) or about 110 grams of meat. Protein balance is dynamic, as in the organism practically are not created a stock of protein, and can be installed in different quantities consumed protein (within certain limits). During growth or recovery after illness (protein starvation) in the body there is heavy delay nitrogen, nitrogen balance becomes positive. The main processes associated with the protein metabolism - deamination of amino acids (see Amino acids), pereaminirovanie (vzaimoponimanie amino acids, proceeding with the transfer of amino groups), amination of ketokislot, the protein into amino acids, finally, the tumor proteins of organs and tissues, including proteins-enzymes. When a positive nitrogen balance is quite intensive processes leading to the synthesis of protein. On the contrary, the lack of protein in the diet leads to a negative nitrogen balance, when the number of emitted nitrogen greater than the amount of nitrogen consumed with food. Partially restore nitrogen balance in this period it is possible by increasing in the diet share of high-calorie fats and carbohydrates. In violation of nitrogen metabolism in the result of some disease occurs azotemia, protein (albumin) appears in the urine.
Cm. also the Metabolism and energy.