[Energetics of active carbohydrate transport into mycoplasma cells]

Abstract

Possible energy supply pathways of active transport of non-metabolized 3-O-methylglucose (3-O-mG) into Acholeplasma laidlawii cells are studied. 3-O-MG transport is sensitive to arsenate, inhibitors of glucolysis and membrane Mg-dependent ATPase (dicyclohexylcarbodiimide) and to uncoupling agents. It is suggested that glycolysis is the main energy source, which main enzymes are found in cell-free extracts. A. laidlawii cells are capable to glycolytic ATP synthesis using glucose as a substrate but not fructose, arginine and ethanol. ATP synthesis is also sensitive to arsenate and glycolytic inhibitors and is resistant to uncoupling agents, dicyclohexylcarbodiimide, valinomycin and nigericin. Probably, hydrolysis of glycolytic ATP by membrane-bound ATPase results in the formation on a membrane of both components of proton-motive force, which supply energy for the active 3-O-MG transport. It is supported with the data on the inhibitor analysis of transport using ionic-selecive antibiotics and lipid-soluble ions.