Catechol-o-methyl transferase is usually localized predominantly in the cytosol fraction of cells, but fractionation of mouse liver showed plasma membranes contain ∼ 70% of the total enzyme activity and have a specific activity ∼ 10x greater than the cytosol fraction. Treatment of the membrane fraction with Lubrol-PX solubilized 47% of the membrane protein and 95% of the enzyme activity. A comparison of Lubrol-solubilized enzyme and [3H]norepinephrine binding activities in a variety of experimental conditions suggest binding is not related to interaction with the active site of catechol-o-methyl transferase. Isoelectric focusing of solubilized membrane proteins showed the enzyme has an isoelectric pH of 4.5-4.8.
|Original language||English (US)|
|Number of pages||10|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Jun 16 1975|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology