Inhibition of mitochondrial electron transport and energy transduction by lutein in vitro
Chaturvedi, V.K.; Kurup, C.K.
Indian Journal of Biochemistry and Biophysics 23(3): 156-161
1986
ISSN/ISBN: 0301-1208 PMID: 3793130 Document Number: 284000
A factor that uncouples mitochondrial oxidative phosphorylation has been purified from chloroplasts and identified as the xanthophyll lutein, based on its chromatographic and spectroscopic characteristics. Lutein stimulated 'State 4' (ADP exhausted) and inhibited 'State 3' (ADP present) respiration of tightly coupled plant and animal mitochondria. The oxidation of NADH was more sensitive to inhibition by the xanthophyll than was the oxidation of succinate or ascorbate. It inhibited the reduction of cytochrome b in submitochondrial particles. Lutein stimulated the dormant ATPase activity of intact mitochondria in the presence of added Mg2+ ions. Uncoupler (2,4-dinitrophenol)-stimulated ATPase activity weas further enhanced by lutein when Mg2+ was present. However, in the absence of Mg2+ ions, it not only did not stimulate dormant ATPase but also inhibited uncoupler-stimulated activity. These properties show the membrane perturbing action of the xanthophyll. The results offer a mechanism by which the two energy transducing organelles of the plant cell may functionally interact to regulate the flow of energy for the optimization of photosynthetic activity.