CHAPTER X. 



CLASSIFICATION OF VEGETABLE PROTEINS. 



A CHEMICAL classification should be based on definite properties of 

 individual substances, but such a treatment of the proteins is at present 

 manifestly impossible. It is, however, desirable to have some scheme 

 by means of which the proteins can be brought together in an orderly 

 fashion. All attempts, thus far made, to classify them have been based 

 chiefly on their solubility under different conditions. This method ot 

 classification has proved in many ways unsatisfactory and inadequate, 

 but seems, for the present, to be the best available. Attempts have 

 recently been made to establish greater uniformity throughout the 

 world in the classification of the proteins and to attach more definite 

 and generally recognised meanings to the various terms and designa- 

 tions which have been used in describing and classifying them. To 

 this end committees were recently appointed by societies in England 

 (608) and America (607) for the purpose of agreeing on a scheme of 

 classification for the proteins. These committees have reported plans 

 which in the main are in agreement with one another, no serious point 

 of difference existing between them. As the scheme of classification 

 of the American committee is more detailed and was prepared to in- 

 clude the vegetable proteins, it is used in this monograph. This 

 scheme provides for the following groups : 



I. The Simple Proteins. 



(a) Albumins. 



(b) Globulins. 



(c) Glutelins. 



(d) Alcohol-soluble proteins (Prolamins). 



(e) Albuminoids. 

 (/) Histones. 

 (g) Protamines. 



II. Conjugated Proteins. 



(a) Nucleoproteins. 



(b) Glycoproteins. 



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