THE ALCOHOLIC FERMENTATION PROPER 325 



The adenosine polyphosphates generated may .serve as phosphate 

 "donors" for the phosphorylation of hexose. Others may pass their 

 phosphate groups to amino acids. The phosphorylated amino acids 

 may then condense with other amino acids to form proteins with the 

 regeneration of inorganic phosphates. Useful work, the synthesis of 

 proteins, would thus be accomplished. Lipmann pictures a phosphate 

 cycle with the following steps: (1) the assimilation of inorganic 

 phosphate with the formation of the primary ester linkage, (2) the 

 generation of energy-rich phosphate bonds by oxidation-reduction 

 reactions, (3) the distribution of energy-rich phosphate bonds by 

 cell catalysts such as the adenylic acid system with the phosphoryla- 

 tion of hexose and/or other compounds, e.g., amino acids, (4) utili- 

 zation of energy in energy-rich bonds to do some useful work as the 

 synthesis of proteins with the regeneration of inorganic phosphate. 

 Only a superficial treatment of this fascinating subject has been at- 

 tempted here. The interested reader is referred to excellent reviews 

 by Kalckar,-* Meyerhof ,^^ and Lipmann -° which deal wdth this 

 subject. 



The Alcoholic Fermentation Proper. Our present-day knowledge 

 of the chemistry of the alcoholic fermentation is the result of investi- 

 gations directed not only toward studying the mechanisms of the 

 alcoholic fermentation per se but also toward studying the mecha- 

 nisms involved in muscle metabolism. Correlative studies in the 

 field of sugar dissimilation in muscle tissues have contributed a con- 

 siderable portion of what is known today of the alcoholic fermenta- 

 tion. The findings of the various investigators have been summarized 

 in the so-called Embden-Meyerhof-Parnas scheme for the dissimila- 

 tion of sugar. 



Essential features of this scheme are given in Table 4. The indi- 

 vidual reactions consist of phosphorylations, intramolecular rear- 

 rangements, oxidation-reductions, dehydration, and decarboxylation. 

 The elucidation of the nature of these reactions is due to Embden, 

 Meyerhof, Parnas, Warburg, Lohmann, Cori, and others. The fol- 

 lowing is a brief resume of the transformations that are believed to 

 occur in the alcoholic fermentation. 



The production of alcohol and carbon dioxide from glucose begins 

 with the phosphorylation of the hexose molecule. Initially, a phos- 

 phate group donated by the adenylic acid system is introduced into 

 the glucose molecule under the mediation of Mg++ (under certain 



ing it up (as a regular part of the system). AMP and ADP can, by accepting 

 phosphate groups, be converted to ATP. 



