ORIGIN OF THE FIRST ORGANISMS 375 



effect of any single enzyme (e.g. laccase or some other oxidase) 

 but consisted of a chain of enzymic reactions which followed 

 one after the other and were co-ordinated in an orderly 

 fashion. 



The same thing was established somewhat later for another 

 important vital phenomenon, that of fermentation. 



L. Pasteur^^ in his day said that: 



The chemical act of fermentation is essentially a phenomenon 

 associated with a vital activity, beginning and ending with that 

 activity ; there is no fermentation without simultaneous organ- 

 isation, development, multiplication of globules or the continua- 

 tion of life by globules which are already formed. 



This supposition was refuted experimentally at the turn 

 of the century by E. Buchner.^^ By using a high pressure, 

 he expressed a juice fi'om yeast which did not contain any 

 living cells but which could nevertheless ferment sugar. 

 Buchner believed that his juice contained a specific enzyme, 

 ' zymase ', which broke the sugar down to alcohol and 

 carbon dioxide by a single chemical act, just as, for example, 

 invertase breaks sucrose down into glucose and fructose. 

 However, the work which continued to be carried out for 

 many years afterwards by a whole constellation of the out- 

 standing biochemists of the first half of the present century, 

 in particular by S. Kostychev, A. Lebedev, C. Neuberg and 

 O. Meyerhof, showed that Buchner's juice contains, not one 

 single enzyme, but a whole complex of such catalysts.^® Each of 

 these accelerates its own specific reaction. All these reactions 

 are combined together to form a long chain of transformations 

 following one another successively in such a way that the end 

 product of the preceding reaction serves as the starting sub- 

 stance for a rigidly determinate succeeding reaction. Sugar, 

 on the one hand, and carbon dioxide and alcohol, on the 

 other, are merely the first and last links of this chain. The 

 reaction catalysed by each separate enzyme of the zymase 

 complex occupies its own essential place in the chain of trans- 

 formations, and forms an indispensable part of the chain as 

 a whole. By poisoning or blocking, one may inactivate selec- 

 tively any single enzyme of the zymase complex and thus 

 exclude the reaction which it catalyses from the general 



