62 



BIOCHEMICAL SYSTEMATICS 



Table 4-2. Taxonomic differences in the synthesis of lysine. 



parative lysine synthesis alone, bacteria, some algae, and higher plants 

 show a closer relationship to each other than to the majority of fungi 

 and Euglena. However, among the fungi, the Saprolegniales and also 

 Hypochytrium catenoides are atypical in that they utilize the di- 

 aminopimelic acid pathway. Such data are clearly of phylogenetic 

 interest, though it is obvious that at present it is uncertain as to how 

 much weight must be given this evidence. 



That higher plants do synthesize a-aminoadipic acid is evi- 

 dent from work by Grobbelaar and Steward (1955) who found that 

 this acid became radioactive after C^* lysine was fed to Phaseolus. 

 Fowden also (personal communication) has noted that a-aminoadipic 

 acid is frequently encountered as a minor or trace component of 

 many plants and that C^^ lysine and tritiated pipecolic acid give rise 

 to radioactive a-aminoadipic acid in Acacia. How these facts will in- 

 fluence, ultimately, the assessment of the phylogenetic implications of 



