cAMP-Mediated Catabolite Repression and Electrochemical Potential-Dependent Production of an Extracellular Amylase in Vibrio alginolyticus

Abstract

  Vibrio alginolyticus, a halophilic marine bacterium, produced an extracellular amylase with a molecular mass of approximately 56,000, and the amylase appeared to be subject to catabolite repression mediated by cAMP. The production of amylase at pH 6.5, at which the respiratory chain-linked H⁺ pump functions, was inhibited about 75% at 24 hours following the addition of 2 μM carbonyl cyanide m-chlorophenylhydrazone (CCCP), while the production at pH 8.5, at which the respiratory chain-linked Na⁺ pump functions, was only slightly inhibited by the addition of 2 μM CCCP. In contrast, the production of amylase in a mutant bacterium defective in the Na⁺ pump was almost completely inhibited even at pH 8.5 as well as pH 6.5 by the addition of 2 μM CCCP.