Studies on the effect of certain enzymic poisons on the metabolism of storage organs IV. Respiration and nitrogen assimilation by radish root slices in relation to feeding with KCN

摘要

At low and high concentrations, respectively, KCN stimulated and inhibited the CO2output of radish root slices. Analysis of tissue slices showed that CO2production is nearly accounted for by the loss in carbohydrates. After 48 hr, the content of protein-N was slightly changed in all the cyanide-treated tissues; whereas, that of soluble-N decreased markedly at high cyanide concentrations and hardly changed at low concentrations. Leakage of soluble-N occurred at high concentrations of cyanide.The nitrogen compounds taken up were incorporated into the nitrogen pool of radish slices. KCN retarded uptake of nitrogen compounds, inhibited their utilization and led to excessive leakage of soluble-N from the tissues into the media. Increased CO2output of slices in nitrogen media was largely accounted for by the loss in carbohydrates from the tissues.High concentrations of cyanide are thought to inhibit CO2output through inhibition of the oxidase system and accompanying phosphorylations. The present results with low concentrations further substantiate the uncoupling theory as a main factor involved in respiration.