Kinetics of dark proton efflux in chloroplasts

FEBS Letters

Schönfeld, Mordechay¹  Kopeliovitch, Bente Sloth¹ 

[1] The Hebrew University of Jerusalem, Department of Agricultural Botany, PO Box 12, Rehovot, Israel

关键词: (Lettuce chloroplast);    Thylakoid membrane;    Proton efflux;    Proton permeability;    Proton binding H+-ATPase;    J H;    initial rate of proton efflux;    P H;    proton permeability of the thylakoid membrane;    C H;    proton-binding capacity of thylakoids;    H x;    amount of protons accumulated by thylakoids;    [H+]i;    [H+]o;    internal and external proton concentrations;    K D;    rate constant for dark proton efflux;   

DOI  :  10.1016/0014-5793(85)80083-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The rate constant for dark proton efflux from preilluminated chloroplasts, was found to be proportional to the proton permeability, and inversely proportional to the ‘proton binding capacity’ of the thylakoids (the ratio between bound and free protons). Dark proton efflux was resolved into two kinetically distinct components: a diffusion-mediated process which was predominant below pH 7, and a separate leakage pathway, characterized by linear dependence on the internal to external proton concentration ratio, which was predominant above pH 7. An increased proton-binding capacity accompanied the increased proton permeability associated with this second pathway.

【 授权许可】

Unknown