title: On the inhibition of p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens by adenosine nucleotides and metal ion complexes.
abstract: The flavoprotein p-hydroxybenzoate hydroxylase is inhibited by adenosine nucleotides, Cibacron blue, phosphate ions and metal ion complexes. The inhibition of the enzyme is competitive with respect to NADPH. The most potent inhibitors of the enzyme are Cibacron blue and the metal ion complexes whereas the inhibition by the adenosine nucleotides is comparable to that by halogen ions. Some inhibitors cause quenching of the fluorescence emission of the protein-bound prosthetic group or perturb the absorption spectrum of the enzyme in the visible region allowing determination of the dissociation constant of the interaction between the free or the substrate-complexed enzyme and the inhibitors. The inhibition constants are in good agreement with the dissociation constants.
mesh_terms: D000227:Adenine Nucleotides / Q000494:pharmacology*; D001667:Binding, Competitive; D004396:Coloring Agents / Q000494:pharmacology; D007700:Kinetics; D008670:Metals / Q000494:pharmacology*; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors*; D011551:Pseudomonas fluorescens / Q000201:enzymology*; D013329:Structure-Activity Relationship; D014227:Triazines / Q000494:pharmacology
chemical_list: D000227:Adenine Nucleotides; D004396:Coloring Agents; D008670:Metals; D014227:Triazines; C012842:Cibacron Blue F 3GA; D006899:Mixed Function Oxygenases; C021385:3-hydroxybenzoate-4-monooxygenase