Membrane transfer of. cap alpha. -tocopherol: influence of soluble. cap alpha. -tocopherol-binding factors from the liver, lung, heart and brain of the rat
The pH of liver supernatant was lowered from 7.4 to 5.1, which removed 23% of the soluble protein and 97% of the lipid-soluble phosphate, increased the total ..cap alpha..-tocopherol transfer activity 1.3-fold and the specific activity of the transfer rate 1.6-fold. This transfer activity was proportional to time up to 4 min and to protein concentrations up to 0.1 mg/ml. Fractionation of the pH 5.1-treated liver supernatant by gel filtration produced a single peak of ..cap alpha..-tocopherol transfer activity of M/sub r/ = 34,000 and a single peak of ..cap alpha..-tocopherol-binding activity which was coincident with the transfer activity. The transfer rate of this peak of activity was 316 pmol/min/mg of protein, a 9-fold purification over the original untreated supernatant. This ..cap alpha..-tocopherol transfer rate was reduced by 83 and 96% following pronase digestion or heat treatment (80/sup 0/C) of the soluble fraction, respectively, while trypsin digestion reduced the transfer rate only 18% and phospholipase C digestion had no effect. Untreated liver supernatant possessed the peak of binding activity of M/sub r/ = 34,000 and a high molecular weight binding fraction that eluted at the void volume. Heart and brain supernatants also possessed an ..cap alpha..-tocopherol-binding fraction that eluted at the void volume, while lung supernatant lacked binding activity.
- Research Organization:
- Univ. of Rochester, NY
- DOE Contract Number:
- AC02-76EV03490
- OSTI ID:
- 5639811
- Journal Information:
- J. Biol. Chem.; (United States), Vol. 256:20
- Country of Publication:
- United States
- Language:
- English
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VITAMIN E
MEMBRANE TRANSPORT
BRAIN
ENZYMES
HEART
HEAT TREATMENTS
INHIBITION
LIPIDS
LIVER
LUNGS
MEMBRANES
MICROSOMES
OXIDATION
PEROXIDES
PH VALUE
RATS
RESPONSE MODIFYING FACTORS
ANIMALS
BODY
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM
CHEMICAL REACTIONS
DIGESTIVE SYSTEM
GLANDS
MAMMALS
NERVOUS SYSTEM
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
OXYGEN COMPOUNDS
RESPIRATORY SYSTEM
RODENTS
VERTEBRATES
VITAMINS
550200* - Biochemistry