■ ■ 



other ways in which the enzyme does not 



li\ the fad thai it resumes ita original activities on 



products. 



Bnzymes, both intracellular and extracellulai 

 wards the i 1 1 1 » i lt .- » i j i < - composition of the medium in which 

 ing. For the intracellular enzymes this is what 

 we bear in mind the profound influence "i" inorganic gaits 

 beal and on cell growth and division. This influei • I 



reaction acidity, etc. on the life of the <-'-ll is bo pronounce 



some observers to believe thai al rmal cell multiplication in ' 



as in tin' case of tumor formation, is due t.. cha a the 



composition of the tissue fluids. Bxtracellula 

 Busceptible to the influence of inorganic ^.ilt s bul 



towards the reacti E the Bolution. In terms of modei 



we may say thai the concentration of II- and OH' ions has a profound 

 influence on the activities of enzymes. Mosl of the eni 



iinal bodj perform their action mally in the presence 



cess «>r OH' ions, thai is. in faintly alkaline redaction. Indeed tin- onlj 

 exception of importance i" iliis is the pepsin of gastric juice, which i 

 mally arts in an acid medium. An \ of either OH' ll 



inhibits tin- activity <>!' tin- enzyme ami usuallv destroys it perma 

 The activities of enzymes air also influenced by Light, man} 

 being destroyed by sunlight; cells Buch as microorganisms 

 affected. 



Before being secreted the <li'_ r <-sti\.' enzym Us whi 



produce them as inactive precursors called I 



in resting gland cells are "t' this nature. Tin- activation 

 or its conversion into tin- enzyme, occurs after it hat 



this has been isidered as another aid t<> <i 



Sometimes the activation does nol occur until the 



some distance along tin- gland duct, as in tin 



enzyme of pancreatic juice. Till it reaches the intestiiv 



trypsinogen tin- zymogen . l>nt it is hei 



like bod} produced by tin- i il epitheliun 



PHYSICOCHEMICAL REFERKM i 



bfonogi aphs and I ' ■ 



Bayliss, W. M.: Principli 



Llip, .1. C: Physical Chemistry, II 



ed, -. 191 1. 

 M. ci. n. lun. .i. 8.: Phj lical I I 



Press, 1917 

 t&tarling, E. II.: Principle* 



