V. RELATIONSHIP OF GENES TO ENZYMES 253 



In fact, vast number of evidences are known to show the existence 

 of intimate relation between genes and enzymes. In some lactobacilli, 

 for example, loss of ability to ferment sorbitol and manitol is correlated 

 with the loss of ability to produce the polysaccharides responsible 

 for specific agglutinability (44). Such a loss of ability to produce the 

 specific " substance is ascribed to a change in the protoplasm pattern 

 brought about by a change in the gene system which the latter is 

 responsible for the change in the agglutinability. Furthermore, in 

 the case of different mutable strains of colon bacilli, colonial dissocia- 

 tion, which shows a genie change, invariably occurs concomitant with 

 the metabolic variation resulting in rapid fermentation of lactose (45). 

 Again, passage of lactobacillus plantarum from the S to the R form 

 is associated with the loss of ability to produce acid from certain 

 sugars (46). Whereas the R form can grow in sugar-free peptone, the 

 S form does not grow in the absence of carbohydrates. It is also 

 reported that the growth of staphylococcus in the presence of strepto- 

 mycin is associated with the emergence of resistant mutants ; at the 

 same time, the emergence is linked with the ability of the cells to 

 synthesize aspartic acid, phenylalanine, etc., in the presence of stre- 

 ptomycin (49). 



It may be possible that each partial pattern of the protoplasm is 

 connected with the action of each enzyme in a cell, so that it may 

 be possible that a certain enzyme is directed chiefly by a certain 

 gene. It cannot be considered, however, that one gene-one-enzyme 

 hypothesis (48) holds always true ; it may rather be reasonable to 

 suppose that, though a certain gene tends to direct chiefly a certain 

 enzyme, an enzyme is generally connected with several genes, or a 

 gene has some connection with several enzymes, for it may rather 

 be exceptional that the property of an enzyme is determined by a 

 restricted partial structure only. 



It is claimed that almost all the proteins present in a bacterial 

 cell are provided with enzymatic action of various kinds (49), a claim 

 which is also raised from the writer's view. The pattern of the pro- 

 teins present in the protoplasm is subjected to the genes, and since 

 an enzyme with a specific active group must be governed by a gene 

 directing chiefly the specific group, the enzyme will be changed with 

 the gene. 



As stated in the previous section, the usual enzymes may not 

 necessarily require for their action the regular polymerization of 

 proteins which is indispensable for the assimilase action, but the 

 polymerization may possibly favour the action of the usual enzymes, 

 for the structural effect of proteins may, in general, be strengthened 

 by the polymerization. Cytoplasmic particles such as mitochondria 



