FIG. 6.

Lactate dehydrogenase is required for the inhibition of glucose uptake. The A. actinomycetemcomitans l-lactate dehydrogenase (ldhA) mutant was suspended in CDM and incubated with no energy source (control) or l-lactate. Radiolabeled glucose was then added, and uptake was examined as outlined in Materials and Methods. Uptake of radiolabeled glucose is expressed as cpm/μg of A. actinomycetemcomitans protein. Experiments were performed in duplicate. Error bars represent the standard deviation and in some cases are too small to be seen.