[Respiratory activity of Acholeplasma laidlawii cells and its role in the active transport of carbohydrates].

The respiratory activity of the Acholeplasma laidlawii cells was studied in order to elucidate a possible mechanism of coupling of transport with energy. The respiration of the cells is stimulated by ethanol, glucose, NADH, lactate, and pyruvate. The substrates of the Krebs cycle have no effect on the respiration. The respiratory activity, stimulated by ethanol and glucose, is inhibited by the inhibitors of the respiratory chain, SH reagents, and the inhibitors of glycolysis. The results of experiments with inhibitors suggest that the respiratory chain in the A. laidlawii cells is reduced and terminated by flavoprotein. This is confirmed by the results of spectroscopic analysis of cytochromes. Respiration coupled with phosphorylation did not play any important role in the active transport of carbohydrates. Probably, the energy, necessary for the transport of carbohydrates, is supplied by the substrate phosphorylation. This explains the activation of respiration by glucose, which is so sensitive to arsenate. The respiration of the A. laidlawii cells is not stimulated by some carbohydrates (fructose, 3-O-methyl-D-glucose).