156 



1. MALONATE 



tobacco leaves was attributed to the presence of preformed precursors or 

 energy donors, so that interference with metabolism during the 2-hr in- 

 cubation does not modify the assembling of the proteins (Stephenson et al., 

 1956). In two instances, glucose is able to partially reverse the effects of 

 malonate. Glucose addition to the Walker carcinosarcoma slices reduces the 

 inhibition by malonate, sometimes restoring the normal rate of protein 

 synthesis (Nyhan and Busch, 1957), and in ascites cell suspensions glucose 

 decreases the malonate inhibition from 92% to 14% (Quastel and Bickis, 

 1959), although the inhibition, is even increased slightly in chick embryo. 

 The marked glycolytic activities of tumor tissue may be responsible for this 

 phenomenon, sufficient energy for protein synthesis being obtained from 

 noncycle pathways. 



The inhibition of amino acid uptake and the synthesis of proteins and 

 enzymes by malonate must be considered in long-term experiments or in 

 whole animal experiments, since this could secondarily affect many other 



