140 COLLEGE BOTANY 



conjugate proteins, so called because of the association of nucleic 

 acid and protein as in nucleo-proteins. They are important 

 constituents of the nuclei, (c) The derived proteins, which 

 are the digested and diffusible protein products (proteoses and 

 peptones), which are necessary in assimilation. The proteins 

 are found throughout the plant, but are usually most abundant 

 in the seeds. Most of the proteids can be digested in the animal 

 body by the enzymes, pepsin and trypsin. 



The proteins are very abundant in certain plants, especially 

 the legumes, and in the seeds of the grain plants. The most 

 important kinds of proteins are: (a) the albumins, found in 

 beans, peas and cereals; (6) the globulins , found most abundant 

 in legumes; (c) the glutenins, found in cereals, especially in 

 wheat and rice; (d} the gliadins, found in the cereals; and (e] 

 the nucleo-proteins, found in the nucleus. Most of the proteins 

 are insoluble in the cell sap of the plant and must be digested, 

 that is, made soluble, before they can be used or moved. This 

 is accomplished by the action of enzymes in a manner similar 

 to that in the animal stomach and results in transformation into 

 peptones, proteoses and similar soluble products. They are a 

 very important and necessary part of our food supply. 



Amides are simpler than the proteins. They are composed 

 of carbon, hydrogen, oxygen and nitrogen and are soluble in the 

 cell sap. They are reserved foods and are found in the under- 

 ground parts of the plant. Among the most important are 

 asparagin, glutenin, trypsin and leucin. 



Tannin and tannoids are astringent products which are used 

 in the manufacture of leather, in medicines, etc. They are ob- 

 tained primarily from the bark and woody parts of our 

 higher plants. 



