Glucose concentration dependent ATP-ase activity in Eschеrichia coli during fermentation and the role of hidrogenase 4

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The dependence of E. coli BW25113 wild type’s and JRG3621 (hyfB-R) mutant’s membrane vesicles ATPase activity on glucose concentration and cooperation of FOF1-ATPase with Hyd-4 (hyf) under different conditions were studied. Different values of the N,N’-dicyclohexylcarbodiimide (DCCD)-sensitive ATPase activity were observed upon 0.2% and 0.8 % glucose fermentation conditions. These values depended on pH and K+ content in the assay medium. DCCD-sensitive ATPase activity of 0.2 % glucose fermented hyfB-R mutant was lower 1.5-fold compared to wild type in K+-free medium, and slightly increased by 100 mM K+. The wild type demonstrated lower ATPase activity in both case, in K+-free and in K+-present media at pH 6.5, respectively ~1.5 and ~2-fold under 0.2% glucose fermentation, compared with pH 7.5. Unlike 0.2 % glucose fermentation, K+ had suppressed effect on wild type's ATPase activity upon 0.8 % glucose fermentation at pH 6.5, whereas hyfB-R showed K+ stimulated ATPase activity at the same conditions. The results pointed out the FOF1-ATPase’s interaction with Hyd-4 and K+ uptake systems upon 0.2% glucose fermentation at pH 7.5 which is important for understanding the role of FOF1and Hyd-4 under fermentation.