FIG. 4.

5-Cl-PZA is not a competitive inhibitor of FAS-I. (A) Purified FAS-I enzyme was incubated for 30 min at 37°C in the presence of different concentrations of 5-Cl-PZA. The treated enzyme was subsequently diluted sevenfold into buffer A (see text) and concentrated on a 100-kDa Centricon concentrator, followed by two washes in a 10-fold excess of buffer A before analysis of fatty acid synthase activity. (B) Purified enzyme was preincubated with 0.030 mg of 5-Cl-PZA/ml for different lengths of time before fivefold dilution into the enzyme assay mix.