Phosphonium compounds as new and specific inhibitors of bovine serum amine oxidase.
TPP+ (tetraphenylphosphonium ion) and its analogues were found to act as powerful competitive inhibitors of BSAO (bovine serum amine oxidase). The binding of this new class of inhibitors to BSAO was characterized by kinetic measurements. TPP+ can bind to the BSAO active site by hydrophobic and by coulombian interactions. The binding probably occurs in the region of the 'cation-binding site'[Di Paolo, Scarpa, Corazza, Stevanato and Rigo (2002) Biophys. J. 83, 2231-2239]. Under physiological conditions, the association constant of TPP+ for this site is higher than 10(6) M(-1), the change of enthalpy being the main free-energy term controlling binding. Analysis of the relationships between substrate structure and extent of inhibition by TPP+ reveals some new molecular features of the BSAO active site.
Dipartimento di Chimica Biologica, Università di Padova, Via G. Colombo 3, 35121 Padova, Italy. marialuisa.dipaolo@unipd.it
Maria Luisa
ML
Di Paolo
Michele
M
Lunelli
Marina
M
Scarpa
Adelio
A
Rigo
D006631:Amine Oxidase (Copper-Containing) / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002417:Cattle; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D009861:Onium Compounds / Q000494:pharmacology*; D009943:Organophosphorus Compounds / Q000494:pharmacology*; D012680:Sensitivity and Specificity; D044967:Serum / Q000201:enzymology*; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
D004791:Enzyme Inhibitors; D009861:Onium Compounds; D009943:Organophosphorus Compounds; D006631:Amine Oxidase (Copper-Containing); C013289:tetraphenylphosphonium