Effector binding sites in plasma amine oxidase.
The interaction between plasma amine oxidase (EC 1.4.3.6) and chlorpromazine was studied by spectroscopic methods. The binding of chlorpromazine to the enzyme is paralleled by an increase in the emission anisotropy of the ligand. Titration of the enzyme with chlorpromazine using fluorescence methods revealed the presence of an heterogeneous population of binding sites characterized by the dissociation constants K1 = 7.4 muM and K2 = 35 muM. A kinetic analysis showed that a change in V and Km is induced by chlorpromazine. The increase in V (5.7 fold) is significant and cannot be attributed to modifications in the chemical structure of the effector chlorpromazine. The results are consistent with the concept that the binding of the effector induces a change in the conformation of the enzyme which is transmitted to the catalytic site.
D000818:Animals; D001665:Binding Sites; D002746:Chlorpromazine / Q000494:pharmacology; D004789:Enzyme Activation; D008024:Ligands; D008433:Mathematics; D008995:Monoamine Oxidase / Q000097:blood; D011485:Protein Binding; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D013552:Swine
D008024:Ligands; D008995:Monoamine Oxidase; D002746:Chlorpromazine