Analysis on the membrane-bound electron transport system in Azotobacter Vinelandii cells grown to different phases of the bacterial growth curve cycle



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The non-pyridine nucleotide dependent oxidoreductase and concomitant oxidase activities associated with the Azotobacter vinelandii electron transport fraction were examined in cells grown to different phases of the growth curve cycle. All cells were grown under nitrogen-fixing conditions, using acetate as the sole carbon source. Early log, late log, and stationary phase cells were harvested and the "R3" electron transport fractions analyzed for both enzyme activities and cytochrome content. The enzymes assayed were the NADH and TMPD oxidases; the pyridine nucleotide independent succinate, L(-)malate, D,L-lactate, and L(+)glutamate oxidases as well as the PMS reductase activities. Analyses of the R3 fractions revealed that the highest concentration of b- and c-type cytochrome components were noted in A. vinelandii cells grown to the late log phase. [...]