Effects of monovalent cations on cytochrome P‐450 camphor evidence for preferential binding of potassium

FEBS Letters

Hui Bon Hoa, Gaston¹  Di Primo, Carmelo¹  Deprez, Eric¹  Douzou, Pierre¹ 

[1] INSERM-INRA U310, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France

关键词: Cytochrome P-450cam;    Cation binding;    Camphor binding;    Spin transition;    Cytochrome P-450cam;    cytochrome P-450 camphor;    Li+;    lithium;    Na+;    sodium;    K+;    potassium;    Rb+;    rubidium;    Cs+;    cesium;    Mg02+;    magnesium;    Ca2+;    calcium;    K d cat;    apparent dissociation constant for the cation;    K d cam;    apparent dissociation constant for camphor;    Δhyd;    cation hydration free energy;    ΔGcam;    camphor binding free energy;    ΔGcat;    cation binding free energy;    ADP;    adenosine-5'-di-phosphate;    ATP;    adenosine;    -5'-triphosphate;   

DOI  :  10.1016/0014-5793(94)00545-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Binding of monovalent cations of increasing ionic radius to ferric cytochrome P-450_cam was measured. Potassium has the highest affinity for the cation binding site observed in the X-ray crystallographic structure with K _{d cat} = 12 mM, compared with the smaller cation lithium, (K _{d cat} = 37 mM) and the larger cation cesium (K _{d cat} = 20 mM). Coupling between cation binding and camphor binding is established by the observation of a linear relationship between the corresponding binding free energies. Potassium binding favours a conformational change of tyrosine 96 which increases the affinity of the protein for camphor and fully dehydrates the active site.

【 授权许可】

Unknown