482 ENZYMES 



contain much protein which undergoes proteolysis before 

 translocation takes place. But no enzyme has been discovered 

 in the seed which is capable of digesting these proteins ; 

 peptidase, however, which can hydrolyse the products derived 

 from the digestion of these seed proteins, is abundant. Dean 

 considers that the protoplasm plays the part of a protease, 

 whilst the peptidase may carry the digestion further. 



The observations of Blagoveschenski * indicate that the 

 protease of a plant splits the globulins characteristic of that 

 plant more actively than the globulins from other sources. 



Peptidase [ereptase], often associated with protease, is 

 more common and is, in fact, almost universally present in 

 the vegetable kingdom. Peptidases are found in abundance 

 in the fruits of Musa,^ of Carica papaya (papain), J of Ananas 

 sativa (bromelin), and in the latex and fruit of Ficus (cradein). 

 They occur in the seeds or seedlings of Catinabis,^ Hordeum, 

 Lupinus, Medicago, Phaseolus, and Ricinus.\\ Also their 

 presence has been noted in Agaricus, Saccharomyces ^ and other 

 fungi. 



Amidases would appear to be more elusive than either 

 protease or peptidase : they may be classed as aminases or 

 amidases according as to whether they split off ammonia 

 from amino groupings or from amide groupings. 



Kato ** found that the juice of bamboo shoots was able to 

 act on asparagine with the liberation of ammonia. Shibata ff 

 separated from the mycelium of Aspergillus niger an amidase 

 which acted on amides and asparagine ; Dernby %% found that 

 the press juice of yeast set free ammonia from asparagine, 

 but was inactive on amino acids ; and Grover and Chibnall §§ 

 have isolated an enzyme from the roots of barley which is 



* Blagoveschenski : " Biochem. Journ.," 1924, 18, 795. 

 •j- Bailey : " J. Amer. Chem. Soc," 1912, 34, 1706. 

 % Vines : " Ann. Bot.," 1908, 22, 103. 

 § Vines : id. 



II Butkewitsch : " Zeit. physiol. Chem.," 1901, 32, i. Jacobson : " J. 

 Amer. Chem. Soc," 1912, 34, 1730. Dean : " Bot. Gaz.," 1905, 39, 321. 

 ^ Vines : "Ann. Bot.," 1905, 19, 171. 

 ** Kato : " Zeit. physiol. Chem.," 191 1, 75, 456. 

 ft Shibata : " Hofmeister's Beitr.," 1904, 5, 384. 

 XX Dernby ; " Biochem. Zeit.," 1917, 81, 107. 

 §§ Grover and Chibnall : " Biochem. Journ.," 1927, 21, 857. 



