152 



THK CHEMISTRY OF THE PLANT 



Protein Group. — Con. 



Enzymes. 



Invertase 

 Cytase 



the less complex, soluble, di- 

 alyzable Albumoses (to which 

 the peptones belong). Other 

 related groups are the Albu- 

 minoidSf some of which are 

 crystallizablc. All of these 

 groups have innumerable 

 forms differing from one 

 another in solubility in acids, 

 alkaUes and salt solutions; in 

 their coagulabihty with heat, 

 salts, acids and alkalies and 

 enzymes; in their power to 

 dialyze, and in the forms of 

 enzymes that can attack them 

 and the forms of the pro- 

 ducts of such enzymatic 

 action. 



These are substances showing 

 many of the characteristics of 

 the protein compounds (e.g. 

 destruction of activity by heat 

 or salts of heavy metals, etc.), 

 but not so complex. They are 

 very numerous, even in the 

 same plant, and perform many 

 of its important functions. 

 They are in a sense ''cataly- 

 zers," in that they start or 

 intensify chemical processes 

 without themselves being used 

 up (or only in relatively small 

 degree) . 



The more important plant en- 

 zymes and the substances 

 acted upon by them are as 

 follows : 



Hydrolyzing saccharose to d- 

 glucose and d-fructose. 

 Hydrolyzing hemicelluloses to 

 • monosaccharids. 



