Inhibition of model compound of purple acid phosphatases on growth of Aerobacter aerogenes investigated by microcalorimetry

Microcalorimetry was used to study the inhibitory or antibiotic action of six kinds of the model compounds of purple acid, phosphatases on a strain of Aerobacter aerogenes. Difference in their capacities to inhibit the metabolism of this bacterium was observed. The extent and duration of the inhibitory effect on the metabolism as judged from the growth rate constant, k, and the half-inhibitory concentration, IC50, varied with the different drugs. The rate constant k of A. aerogenes (in the log phase) in the presence of the compounds decreased with the increasing of concentrations. The experimental results reveal that the order of the antibiotic activity of the compounds is: LD-1>LD-2>LD-3>XF-1>LD-4similar toLD-5.