Preparation and partial purification of soluble choline dehydrogenase from liver mitochondria

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Abstract
Treatment of mitochondria with lipase or trypsin released choline dehydrogenase into solution. After precipitation of the dehydro-genase preparation with ethanol, however, the enzyme could not be re-dissolved in buffer, although it still possesses activity. Ultrasonic disintegration of mitochondria released some choline dehydrogenase into solution. The enzyme was not sedimented by ultracentrifugatlon. The yield of soluble enzyme is, however, quite low. A combination of ultrasonic disintegration and butanol extraction of mitochondria gave a successful procedure for obtaining soluble choline dehydrogenase. The enzyme remained in the supernatant fluid after centrifuging at 173,000 G for 90 minutes; it could be precipitated with ethanol and redissolved at will. Initial steps in the partial purification of the soluble choline dehydrogenase, using ethanol fractionation and selective adsorption on calcium phosphate gel, were reported.