Action of valinomycin in uncoupling corn mitochondria

Journal Article · Wed Jan 01 04:00:00 EST 1975 · Plant Physiol.; (United States)

DOI:https://doi.org/10.1104/pp.56.1.13· OSTI ID:7196824

Hensley, J R; Hanson, J B

Valinomycin in the presence of potassium is a potent uncoupler of corn (Zea mays L.) mitochondria, eliminating respiratory control. Valinomycin produces higher steady state potassium phosphate swelling which can be reversed to give active shrinkage if mersalyl is added to block the Pi/sup -//OH/sup -/ antiporter. Respiration declines concurrently. Uncouplers accelerate the shrinkage and restore the respiration. The same results can be obtained with sodium phosphate if gramicidin D is substituted as ionophore. It is concluded that valinomycin uncoupling is the result of cyclic salt transport, with influx pumping of potassium phosphate via the Pi/sup -//OH/sup -/ antiporter and efflux pumping via a K/sup +//H/sup +/ antiporter. The result is a higher level of steady state swelling, rapid turnover of the proton gradient, and uncoupled respiration rates. The level of steady state swelling can be manipulated by varying the valinomycin or K/sup +/ concentrations, with high concentrations favoring activation of the efflux pump. A mosaic membrane model with high resistance for proton and monovalent cation penetration to the cation/sup +//H/sup +/ antiporter is used to explain the results. (auth)

• Research Organization: Univ. of Illinois, Urbana
• OSTI ID: 7196824
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 56; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

551000* -- Physiological Systems
59 BASIC BIOLOGICAL SCIENCES
ALKALI METAL COMPOUNDS
ALKALI METALS
ANTIBIOTICS
BIOCHEMISTRY
BIOLOGICAL MODELS
BIOMASS
CELL CONSTITUENTS
CEREALS
CHEMISTRY
DRUGS
ELECTRON TRANSFER
ELEMENTS
ENERGY SOURCES
ENZYMES
GRAMINEAE
GRASS
MAIZE
MEMBRANE TRANSPORT
METABOLISM
METALS
MITOCHONDRIA
ORGANOIDS
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
PLANTS
POTASSIUM
POTASSIUM COMPOUNDS
POTASSIUM PHOSPHATES
RENEWABLE ENERGY SOURCES
RESPIRATION