Abstract: A method for modulating the activity of an AMP-forming enzyme (AFE) is disclosed. The method is based upon the novel observation that the activity of these enzymes is controlled by acetylation of the enzymes to inactivate them and de-acetylation of the enzymes to re-activate them. The acetylation of the enzyme occurs at a characteristic lysine residue. Various polypeptides, nucleic acids and other molecules that are related to modulating the AFE activity are also disclosed. Further disclosed are methods of modulating cellular acetyl-CoA or propionyl-CoA levels in bacterial hosts, methods of identifying agents that can modulate the activity of AFE acetylases, and methods of identifying AFE mutants that are insensitive to acetylation regulation.

Abstract: It is disclosed that the enzymes ATP:corrinoid adenosyltransferase (CobA) from Salmonella typhimurium and reduced flavodoxin (FldA) from E. coli are both necessary and sufficient, in the presence of ATP, to reduce the oxidation state of the cobalt atom in cobalamin and produce adenosylcobalamin. This makes possible the construction of plasmids to confer upon microbial fermentation hosts the ability to synthesize adenosylcobalamin, the supply of which can sometimes be a limitation on microbial growth in fermentation. Since the enzyme flavodoxin reductase (Fpr), also from E. coli, can act to reduce FldA for biological activity, that enzyme should preferably be expressed in a fermentation host as well.

Abstract: A method for modulating the activity of an AMP-forming enzyme (AFE) is disclosed. The method is based upon the novel observation that the activity of these enzymes is controlled by acetylation of the enzymes to inactivate them and de-acetylation of the enzymes to re-activate them. The acetylation of the enzyme occurs at a characteristic lysine residue. Various polypeptides, nucleic acids and other molecules that are related to modulating the AFE activity are also disclosed. Further disclosed are methods of modulating cellular acetyl-CoA or propionyl-CoA levels in bacterial hosts, methods of identifying agents that can modulate the activity of AFE acetylases, and methods of identifying AFE mutants that are insensitive to acetylation regulation.