Abstract
Summary
The effects of fluoride, of anaerobiosis, and of iodoacetate upon esterification of phosphate by homogenates, by particles, and by supernatant fractions of liver, brain, and tumor have been determined. The requirement for DPN by the various fractions has also been investigated.
1. Phosphorylation by the homogenates or particles increases with addition of fluoride up to an optimum concentration of about 0.01 M; optimum phosphorylation by the supernatant fractions is obtained when fluoride is omitted entirely. By this adjustment of fluoride concentration the preponderance of glycolytic over oxidative phosphorylation in the Walker 256 tumor is even more marked than has been previously recognized. 2. Under the present experimental conditions phosphorylation by the particulate fractions of liver and brain and of tumor within the range of experimental error was found to be dependent on aerobic processes, while that in the supernatant fractions was completely dependent on anaerobic reactions. The maximal values obtained with the supernate fractions under anaerobic conditions for the ratio of phosphorus uptake to lactate formation were: liver, 0.7; brain, 1.5; tumor, 1.2. 3. Phosphorylation by the particulate and supernate fractions was markedly inhibited by iodoacetate; no significant differences between the sensitivity of the tumor fractions and that of the liver or brain fractions was observed. 4. Phosphorylation in the Walker 256 tumor appears to differ from that in normal tissues principally in quantitative rather than in qualitative respects.
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