MODE OF ACTION OF ZYMASE 97 



The phosphate added enters into a combination with the glucose. 

 What demonstrates this is the fact that the phosphate is not able to 

 be obtained again by the usual magnesium salt. Harden and Young 

 have thought that the phosphate united to two half molecules of the 

 hexose. The remaining half molecules, with three atoms of carbon, 

 gave alcohol and carbon dioxide. The combination of hexose-phos- 

 phate is transformed by an enzyme hexose-phosphatase which re-forms 

 a new combination with two remnants of the hexoses. The phos- 

 phate, then, follows a cycle and it is the quickness with which the 

 phosphate traverses this cycle that determines the speed of fermenta- 

 tion. 



Lebedeff has produced an important contribution in relation to 

 this conception. He has been able to prepare the osazones, phenyl- 

 and bromophenylhydrazones of this hexose-phosphate. He has iso- 

 lated and analyzed the calcium salt. The following formula is given 

 to this body C 6 HioO4(R 2 PO 4 )2, resulting from the condensation of two 

 molecules of C 3 H 5 O 2 I^PO4. 



Young developed the following formula with either an aldehyde 

 or ketone group free to form hydrazones: 



CHO 



CH-P0 4 H 2 

 (CH-OH) 3 

 CH-P0 4 H 2 



According to Lebedeff alcoholic fermentation takes place accord- 

 ing to the following equations: 



1. C 6 Hi 2 O 6 = 2 (C 3 H 6 3 ). 



2. 2 (C 3 H 6 O 3 ) + 2 RHPO 4 = 2 (C 3 H 5 O 2 RPO 4 ) + 2 H 2 O. 



3. 2 (C 3 H 5 O 2 RPO 4 ) = C 6 H 10 O 4 (RP0 4 ) 2 . 



4. C 6 H 10 4 (RP0 4 ) 2 + H 2 = C 2 H 5 OH + CO 2 + C 3 H 5 O 2 + 2 (RHP0 4 ) 



or even 



5. C 6 H 10 4 (RP0 4 ) 2 + 2 H 2 = 2 (C 2 H 5 OH) + 2 C0 2 + 2 (RHPO 4 ). 



This scheme involves the following; 



Decomposition of the hexose into 2 molecules of triose (dioxy- 

 acetone). 



Union of one molecule of the triose with 1 molecule of phosphate; 

 a phosphoric ether results. 



Condensation of two molecules of this phosphoric ether with one 

 molecule of hexose-phosphate. 



Decomposition of this hexose-phosphate into phosphate, alcohol 

 and carbon dioxide. 



