Effect of methyl-cyclodextrin on adenylate cyclase activity of Bordetella pertussis.

The activity of Bordetella pertussis extracytoplasmic adenylate cyclase (AC) decreased during decelerating growth phase in a Stainer-Scholte medium. Neither proteolytic activity nor virulence variation (phase variation; antigenic modulation) appears to be responsible for the observed activity fall. The addition of methyl-β-cyclo-dextrin enhances AC activity and prevents the inhibition of AC activity by fatty acids. Cyclodextrin could entrap inhibitors increasing in this way the AC activity. These results show that the inclusion of cyclodextrin in the culture medium increases the AC activity.