10 PRINCIPLES OF FEEDING FARM ANIMALS 



c. Prolamins are insoluble in water and soluble in 70 to 90 per cent 

 alcohol. To this class belong gliadin, found in wheat and rye grain ; hordein 

 in barley, and zein in corn. 



d. Glutelins are insoluble in water, salt solutions, or alcohol, and 

 soluble in dilute alkali solutions. Glutenin belonging in this group is found 

 in seeds of wheat, barley, oats, and corn. 



The following summary shows the simple plant proteins that have 

 been identified in cereals and some other seeds ; the approximate percentages 

 present in each case, as given by Osborne, are stated. 



In wheat grains: Leucosin, 0.3; edestin, O.G; gliadin, 4.25, and 

 glutenin, 4.0. 



Rye: Leucosin, 0.4; gliadin, 4.0. 



Barley: Leucosin, 0.3; hordein, 4.0; glutenin, 4.5. 



Oats: Avenalin, 1.5; glutenin, 11.25. 



Corn: Maysin, 0.25; edestin, 0.14; zein, 6.1, and glutenin, 3.8. 1 



Peas: Legumelin, 2.0; legumin and vicilin, 10.0. 



Flaxseed: Edestin, 17.6. 



Horse beans: Legumelin, 1.5; legumin and vicilin, 13.0.. 



2. Conjugated or Modified Proteins. These substances have been modi- 

 fied so as to possess different chemical and physical properties from the 

 simple proteins thus far considered, either through combinations with other 

 compounds, or through the action of ferments, heat, or chemicals. The 

 nucleoproteins belong to this group, of which the best known is casein of 

 milk. They contain phosphorus in addition to the elements that are 

 always found in protein substances. 



3. Derived Proteins. These are intermediate bodies formed in the 

 cleavage of the protein molecule in the process of digestion; they are 

 diffusible and are assimilated by the living cell for use in the building 

 up (synthesis) of true proteins. Proteose and peptones are the more 

 important representatives of this class. On further cleavage they are 

 changed into amino acids, the final decomposition products formed in the 

 digestion of protein substances. The amino acids are the primary build- 

 ing materials out of which the protein substances of the animal body are 

 formed. The different protein substances vary greatly in the proportions 

 of amino acids into which they may be broken up; the differences in the 

 nutritive effects of proteins of different origin that have been observed 

 appear to be intimately connected with this fact. 



Amino Acids and Amides. Both amino acids and amides are 

 protein substances of simpler molecular structure than those con- 

 sidered in the preceding paragraphs. The former are found free in 

 only small amounts in plants, while amides occur in abundance in 

 the sap of green a*nd young plants, especially after sprouting, as 

 well as in all immature plant materials. The best known amides 

 are asparagin, found in young asparagus, peas and beans ; glutamin 

 and betain, found in the beet root, etc. The amides are inter- 

 mediate products formed in the living plant from inorganic ma- 

 terials (nitric acid or ammonia), and are later changed into complex 

 protein substances. They are also formed in the decomposition of 

 proteins through the action of bacteria and molds, hence are 

 always present in silage and other fermented feeds. 



1 Assumed. 



