BIOLOGICAL TRANSPORT 



mediary metabolism appears more and more to be fundamentally 

 similar in all cells, the characteristic, differential, chemical prop- 

 erties of different cells should depend largely on their permeases. 



These chemical connecting links to the outside world are surely 

 the same ones which Hober described early in this century as "the 

 physiological import and export" of the cell (1911). In the absence 

 of a unique demonstration of their makeup and operation, we should 

 be reluctant to accept at this point a new name for the transport 

 processes of all cells, if this was intended, and even more reluctant 

 to accept a unique term for bacterial transport processes in the 

 absence of a sharp differentiation of their nature and function. 



The probable relationship of transport to enzyme action has 

 long been recognized. Danielli wrote this summary statement in 

 1954: "The general conclusion which emerges from these studies 

 is that enzyme-like membrane components appear to be active both 

 in facilitated diffusion and active transport." At the same time he 

 urged reserve in treating the enzymatic aspects as perhaps only 

 incidental to the permeation process. In summarizing studies extend- 

 ing back to 1922, Wilbrandt wrote in the same year (1954), "The 

 assumption that enzymatic reactions are somehow involved in active 

 transport . . . has rather generally been made and in fact can hardly 

 be doubted." Nevertheless, these and many other investigators re- 

 frained from giving the enzyme or the enzymatic process a name. 

 The Commission on Enzymes of the International Union of Bio- 

 chemistry (1961) has ruled that a term containing the -use suffix 

 should be adopted only for a single enzyme catalyzing a known 

 reaction. This renders official an already widely felt restraint. 



If the new term should indeed prove generally acceptable to the 

 whole transport field, the main difficulty of having the term used 

 as if it represented processes peculiar to microorganisms will be 

 avoided. 



I 12 



