Isolation and purification of mitochondrial monoamine oxidase B from bovine liver by chromatofocusing

Mitochondrial monoamine oxidase B has been isolated and purified from bovine liver. The isolation procedure involves (a) a series of purification steps including isolation of the mitochondria, extraction with non-ionic detergents and chromatofocusing; (b) a novel fluorimetric titration assay. The purified enzyme is isolated following a 8.8 fold purification with an overall yield of 12% and a specific activity of 3460 nM.g-1. A comparison is made with other established procedures. Ion exchange chromatography on DEAE-Cellulose produced a 6.8 fold purification, 6.2% yield and 2383.3 nM.g-1 specific activity while with affinity chromatography on Blue Sepharose CL-6B gave a 3 fold purification, 4.1% yield and a specific activity of 1152.7 nM.g-1.