220 A SYMPOSIUM ON RESPIRATORY ENZYMES 



lytical method for measuring the disappearance of oxalacetic acid. 

 The latter workers studied chiefly the reactions, glutamic acid plus 

 pyruvic acid, and alpha-ketoglutaric acid plus diflFerent amino acids. 



Quantitative studies of the rate of transamination in different 

 tumors and embryonic tissue have been carried out by Cohen and 

 Hekhuis (16). In their study a series of mouse tumors and cat em- 

 bryonic tissues were shown to have low rates of transamination as 

 compared with normal adult tissue. Further, the writer has shown 

 (63) that the transaminase activity of liver from rats fed dimethyl- 

 aminoazobenzene decreases progressively to a low value in the 

 hver tumors arising in these animals. It thus appears that rapid 

 growth, or increased protein synthesis, is associated with a low 

 transaminase activity. 



Plant Tissues.— Euler et al. (27) reported transaminase activity in 

 higher plants, but no data were pubhshed in support of this state- 

 ment. Virtanen and Laine (41) state that transamination between 

 oxalacetic acid and alanine takes place in crushed pea plants. 

 Transaminase activity in extracts prepared from pea, lupine, and 

 pumpkin seedlings has been reported by Kritzmann (24). Cedran- 

 golo and Carandante (42) studied transamination in leguminous and 

 graminaceous plants. Dialyzed extracts of seeds and sprouts were 

 used and were prepared by the same method as that employed by 

 Adler and Sreenivasaya (43) for the preparation of formico- 

 dehydrogenase. The systems Z(— )-aspartic acid plus pyruvic acid, 

 Z(— )-aspartic acid plus alpha-ketoglutaric acid, and alpha-keto- 

 glutaric acid plus Z( + ) -alanine were investigated. Experimental 

 data are not presented in this paper, but rather the relative veloci- 

 ties of the above reactions in graminacae seeds and sprouts as com- 

 pared with leguminous seeds and sprouts, which are assigned an 

 arbitrary value of 100. The graminacae extracts are reported to be 

 1.5 to 2.5 times as active as those from legumes. According to these 

 authors, the lack of aspartic acid utilization by graminacae, re- 

 ported by Virtanen, cannot be due to the lack of a transaminating 

 enzyme. Of interest is the finding of these workers that dialyzed 

 plant extracts are active. As previously mentioned, Kritzmann (25) 

 reported that dialysis inactivates transaminating enzymes from 

 plant sources. 



Experiments with Chlorella (63) by the author failed to show 

 any evidence of transaminase activity with the systems alpha- 

 ketoglutaric acid plus Z(+) -alanine, and alpha-ketoglutaric acid plus 

 Z( — ) -aspartic acid. 



