Catalysts of Organic and Inorganic Origin. 



297 



Malt diastase 



Do. + HA 

 Papain 



Do. + H. ; 0., 

 Pepsina porci 



Do. + HA 

 Pancreatin 



Do. + H 2 2 

 Potato powder 



Do. + HA 

 Apple powder 



Do. + H.,0., 



~ - 



c3 w 









... . 













•g 







— 





S3 



So 

 o 



3 



| 



rosin. 







p"» 

 Ph 







H 



+ 













+ + + 



+ 



+ 

 + 









+ 



+ 



+ 









+ 













+ + + 





+ 









+ + + 



+ + 



+ + + 



+ + 







+ + + 



+ + 



+ 





+ 





+ + + 



+ + + 





+ + 



+ + 





Neither the chlorides nor the phosphates of potassium or sodium accelerate 

 the oxidase action of malt diastase. If anything the addition of malt diastase 

 to potassium phosphate appears to slightly retard the feeble oxidase action of 

 the latter, especially to ursol tartrate. Sodium or potassium bromide enfeebles 

 the blue reaction of diastase with guaiacum and H 2 2 . 



The watery or glycerine extract of apples, or the pounded pulp, gives a 

 .reaction with ursol tartrate in the absence of hydrogen peroxide, but not 

 potato pulp or its oxidase extract. Living slices of potato give a surface 

 reaction after a day's immersal and the pounded pulp or oxidase extract gives 

 a faint reaction on long standing. According to Moore and Whitley this 

 would be due to its being a " peroxidase " only able to act when peroxidases 

 developed on the surface. If so it is difficult to understand why both apple 

 and potato oxidase and pulp should at once give a blue guaiacum free from 

 peroxide. Rapidly expressed and boiled apple sap contains no trace of hydrogen 

 peroxide and has no perceptible action on ursol tartrate, but if it is added to 

 pounded potato pulp or oxidase extract, the latter now gives a distinct and 

 fairly rapid oxidase action with ursol tartrate, which is not accelerated further 

 by the addition of salt or other sensitisers. Evidently apple sap contains a 

 sensitiser which is absent or deficient in potato pulp and which is not an acid, 

 for no reaction with ursol tartrate is produced by the addition of dilute 

 hydrochloric, oxalic, citric, malic, or tartaric acids to the potato pulp. 



Apple ash is rich in potassium, which occurs mainly as phosphate and 

 carbonate. Acid potassium phosphate and normal potassium carbonate have 

 little or no accelerating action on potato oxidase. If they are mixed 

 so as to produce a neutral solution and a small amount added to 

 potato oxidase, the latter will oxidise both ursol tartrate and tannic acid, 



