206 PLANT PHYSIOLOGY 



solution, thus preparing a solution of the colloidal metal which 

 had the following characteristics of enzymes: 



1. They had an optimum temperature. 



2. They had an optimum acidity. 



3. They were poisoned or inhibited by hydrocyanic acid and 

 other toxins. 



4. They acted both synthetically and analytically. 



5. They were colloidal. 



QUESTIONS 



1. Why does sweet corn lose its sweetness unless cooked soon after its 

 removal from the plant? 



2. What is the source of the production of enzymes? 



3. What is fermentation? 



4. Distinguish between catalase and catalyze. 



5. Compare the effect of heat on dry and moist enzymes. 



6. Distinguish between an inhibitor and an antienzyme. 



REFERENCES 



Armstrong, E. — Enzyme action in the light of modern theories of catalysis. 



J. Soc. Chem. Ind., 41:110, 1922. 

 Falk, K. — A chemical study of enzyme action. Science, 47:423, 1918. 

 Horowitz, B. — What are enzymes? Sci. Mo., 6:253, 1918. 

 McDowall, R. J. — Recent work on enzyme action. Sci. Prog., 15:406, 1921. 



