Effect of vanadyl ions on calcineurin and its A subunit.
Calcineurin (CN) exhibits a bimodal regulation by different concentrations of vanadyl ions (VO2+) in the presence of Mn2+. Low concentrations of VO2+ inhibit the enzyme, with 50 microM VO2+ completely inhibiting CN activity, while high concentrations, up to 500 microM VO2+, stimulate the CN activity. A similar bimodal regulation of CN was not observed with either calcium or vanadate under the same conditions. X-band electron spin resonance spectroscopy, used to study the binding of VO2+ to the catalytic subunit A of calcineurin, show that there are two kinds of binding sites in the A subunit.
Wei
Q
Q
Department of Biochemistry and Molecular Biology, Beijing Normal University, China.
Yan
L
L
D000818:Animals; D019703:Calcineurin / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology; D002147:Calmodulin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004578:Electron Spin Resonance Spectroscopy; D020536:Enzyme Activators / Q000378:metabolism / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D011485:Protein Binding; D051381:Rats; D014638:Vanadates / Q000378:metabolism / Q000494:pharmacology*
D002147:Calmodulin; D020536:Enzyme Activators; D004791:Enzyme Inhibitors; D014638:Vanadates; D008345:Manganese; D019703:Calcineurin; D002118:Calcium