194 



A. M. MAYER 



TABLE II 



THE EFFECT OF COUMARIN //; VIVO AND /// vitl'O ON THE ENZYMATIC ACTIVITY 

 OF VARIOUS HYDROLYTIC ENZYMES IN GERMINATING LETTUCE SEEDS 



In vivo: seeds germinated in coumarin solutions (100 p. p.m.). The enzyme 

 assays were carried out in the absence of coumarin. 



In vitro: seeds germinated in water and coumarin was added to the reac- 

 tion mixture. 



Enzyme 



Effect on activity 



in VIVO 



Effect on 

 activity Reference 

 in vitro 



Lipase, neutral Inhibits increase in activity 



Inhibits strongly 



Lipase, acid 

 Phytase 



Activity remains as in dry seeds 



Inhibits increase in activity No effect 



Activity remains as in dry seeds 



Strong inhibition Slight inhibition 



3 

 3 

 6 



falls again in seeds germinated in thiourea^ (Table II, III). 

 Despite these changes in the lipase itself the fat metabolism is 

 far less profoundly affected by thiourea. Total breakdown is 



TABLE III 



THE EFFECT OF THIOUREA in vivO AND in vitrO ON THE ACTIVITY OF SOME 

 HYDROLYTIC ENZYMES IN GERMINATING LETTUCE SEEDS 



In vivo: seeds germinated in thiourea (1250 p. p.m.). No thiourea present 



in the reaction mixture. 

 In vitro: seeds germinated in water and thiourea added to the reaction 



mixture. 



Enzyme 



Effect on activity 

 in vivo 



Effect on 

 activity Reference 

 in vitro 



Lipase, neutral Increase, then decrease 



Lipase, acid Inhibition progressing with time 



Phytase No effect 



Inhibition 3 



No effect 6 



