RESUMO
Organophosphate (OP) pesticides, monocrotophos (MCP), dichlorvos (DDVP) and phosphamidon significantly inhibit both MAO-A and MAO-B activities in rat brain mitochondria. The inhibition of MAO-A by MCP is reversible whereas the inhibition by DDVP and phosphamidon is irreversible. MAO-B is inhibited irreversibly by all these organophosphates suggesting that the mechanism of action of OP pesticides is through phosphorylation of serine residue present in active centre of MAO.
Assuntos
Animais , Benzilaminas/metabolismo , Encéfalo/enzimologia , Inseticidas/metabolismo , Masculino , Mitocôndrias/enzimologia , Monoaminoxidase/metabolismo , Compostos Organofosforados , Oxirredução , Ratos , Ratos Wistar , Serotonina/metabolismoRESUMO
Binding of penicillin amidase from E. coli 436 to aniline-, benzylamine- and phenylethylamine-Sepharose was studied. Binding of the enzyme to aniline-Sepharose was exclusively due to hydrophobic interactions. Benzylamine-Sepharose binds the enzyme due to affinity interactions in the absence of ammonium sulphate and due to hydrophobic interactions in the presence of ammonium sulphate. A conformational change in the penicillin amidase molecule due to ammonium sulphate there by exposing the side chain binding site as a hydrophobic core is suggested.