Calcium transport in vesicles energized by cytochrome oxidase
- Univ. of Rochester, NY (United States)
Experiments on the reconstitution of cytochrome oxidase into phospholipid vesicles were carried out using techniques of selectivity energizing the suspensions with ascorbate and cytochrome c or ascorbate, PMS, and internally trapped cytochrome c. It was found that the K+ selective ionophore valinomycin stimulated the rate of respiration of cytochrome oxidase vesicles regardless of the direction of the K+ flux across the vesicle membranes. The stimulation occurred in the presence of protonophoric uncouplers and in the complete absence of potassium or in detergent-lysed suspensions. Gramicidin had similar effects and it was determined that the ionophores acted by specific interaction with cytochrome oxidase rather than by the previously assumed collapse of membrane potentials. When hydrophobic proteins and appropriate coupling factors were incorporated into the cytochrome oxidase, vesicles phosphorylation of ADP could be coupled to the oxidation reaction of cytochrome oxidase. Relatively low P:O, representing poor coupling of the system, were problematical and precluded measurements of protonmotive force. However the system was used to study ion translocation.
- Research Organization:
- Univ. of Rochester, NY (United States). Dept. of Radiation Biology and Biophysics
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- EY-76-C-02-3490
- OSTI ID:
- 6252979
- Report Number(s):
- UR--3490-1549(Vols.1-2)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
60 APPLIED LIFE SCIENCES
ADP
ALKALINE EARTH METALS
ANTIBIOTICS
BIOCHEMICAL REACTION KINETICS
CALCIUM
CHARGED PARTICLES
CHEMICAL REACTIONS
CYTOCHROME OXIDASE
CYTOCHROMES
DATA
DATA FORMS
DIFFUSION
DRUGS
ELEMENTS
ENZYMES
ESTERS
EXPERIMENTAL DATA
GRAPHS
INFORMATION
ION EXCHANGE
IONS
KINETICS
LIPIDS
MEMBRANES
METALS
NUCLEOTIDES
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXIDASES
OXIDATION
OXIDOREDUCTASES
PHOSPHOLIPIDS
PHOSPHORYLATION
PIGMENTS
POTASSIUM IONS
PROTEINS
REACTION KINETICS
RESPIRATION
VALINOMYCIN