TRANSAMINATION 219 



Q values for the same tissues (32) and in most instances exceed the 

 cytochrome oxidase Q values (32, 33). 



The Qt values with the systems glutamic acid plus pyruvic acid, 

 and aspartic acid plus pyruvic acid, are comparatively low in all 

 tissues studied except liver. The higher rates of transamination in 

 liver are probably due to the fact that pyruvic acid is converted 

 into oxalacetic and alpha-ketoglutaric acids in this tissue (15, 34, 

 35, 36). 



Table 1.— Values of Qt in difiFerent rat tissues 



It is apparent from the data in Table 1 that transamination is 

 chiefly concerned with the substrates glutamic acid plus oxalacetic 

 acid. The metabolic importance of this will be discussed later. 



Breusch (37) reported some experiments on transamination in 

 different tissues with the system glutamic acid plus oxalacetic acid. 

 The following Qt values for various minced cat tissues were cal- 

 culated from his data: muscle, 19.7; liver, 14.1; kidney, 22.5; lung, 

 22.5; embryonic muscle, 14.1; brain, 19.7; and washed erythrocytes, 

 2.8. These values are all much lower than those reported for cat tis- 

 sues by Cohen and Hekhuis (16). Breusch claims that lung tissue 

 is an excellent source of transaminase, since it is free of many 

 dehydrogenase systems. Cohen and Hekhuis, on the contrary (15), 

 found lung to have a low transaminase activity. The method of 

 oxalacetic acid determination used by Breusch (4) for measuring 

 transamination is far from satisfactory and probably accounts for 

 the results obtained. 



Karayagina (38) found that ?(— )-aspartic acid reacts with pyruvic 

 acid to form alanine in skeletal and cardiac muscles, in liver, kidney, 

 and brain, but not in testes. 



Malignant and Embryonic Tissues.— Euler, Giinther, and Fors- 

 man (39) and Braunstein and Azarkh (17) reported low transamina- 

 tion values for tumors. The former workers used a quaUtative ana- 



