Nitrogen foods

Excess carbamoyl phosphate exits to the cytosol, where it stimulates pyrimidine nucleotide biosynthesis. The resulting mild orotic aciduria is increased by high-nitrogen foods. 

Many substances of the greatest importance contain two or more characteristic groups. The alcohol-acids occur in nature as constituents of fruits. The amine-acids and amide-acids occur in fruits and vegetables, and are important products of the decomposition of nitrogenous foods. Ketone-esters are much used in the preparation of other compounds. The ketone-alcohols and aldehyde-alcohols form the important class of substances known as carbohydrates. Only a few of the more important and typical mixed compounds will be considered here. 

At present, much more value is attached to the final products of hydrolysis, to the mono- and di-amino-acids, than to all the substances which precede them in the degradation of nitrogenous foods. Many writers believe that these products through a retrogressive metamorphosis in the digestive mucous membranes form the various albuminoids appropriate to the... 

Casein is the most important protein body in milk. Besides its chief function as nitrogenous food it plays the important role of protective colloid for the fat particles and also for calcium phosphate with which it forms a colloidal combination. It keeps the fat particles in a fine state of emulsion and prevents them from uniting into clots, probably due to the formation of a fine membrane around the particle. Casein may be precipitated from milk by acids. It is insoluble in water and also in the solutions of neutral salts, except sodium fluoride and potassium oxalate. Casein has acid properties, drives carbon dioxide out of carbonates, and is soluble in alkalis. The ammoniacal solution possesses a high protective effect toward colloidal gold. The gold number 0.01 indicates that it belongs therefore to the protective colloids of the first class. The behavior toward bases has been care-... 

Proteins.— The nitrogenous food materials make up 10-16 per cent, of the solids of the human diet, and may reach 30 per cent, if the consumer can afford them. They are the most expensive and most palatable part of the dietary, and are well represented in eggs, meat, fowl, fish, milk, cheese, nuts, cereals, and legumes (beans, peas, lentils). Proteins form the only dietary source of amino acids, the content of which differs in different proteins. For this reason, it is generally believed that about half of the food protein should be derived from animal sources to ensure getting a sufficient supply of the correct amino acids, and several sorts of protein are included in the dietary so as to provide an adequate selection. 

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