Abstract
Activities and properties of two NADP-linked isocitrate dehydrogenases which differ in its location, and transhydrogenase are ex-amined in tumor bearing rat liver and ascites tumor cells. Neither isocitrate dehydrogenase nor transhydrogenase of liver showed any significant change in specific activity during tumor growth, but the activities of these enzymes per unit DNA decreased daily.
There was no significant difference bet-ween the specific activities of AH-130 tumor cells' mitochondrial enzyme and the liver mitochondrial enzyme on the basis of mito-chondrial protein, but the soluble enzyme of tumor cells showed only one fifth to one tenth of the activity of that of the liver.
Isocitrate dehydrogenase in the AH-130 tumor cells showed and lower sensitivity to PCMB than that in the liver. Soluble iso-citrate dehydrogenase showed about two-fold sensitivity to PCMB, compared with mito-chondria) isocitrate dehydrogenase in both the AH-130 tumor cells and the liver.
Adenine nucleotides have no significant effect on the enzyme activity.
