Scientia Sinica

SCIENTIA SINICA

Vol. V

Table 2. Activities’and Yields of Succinic Dehydrogenase in the Different Steps of Purification.

i

Purification Steps Volume, ml Yield, % Specific Activity

Cytochrome c-deficient heart muscle

, 2000 ; 100 Aqueous extract after n-butanol treatment _ 1400 35 Eluate from Ca phosphate gel ° 1200 21 First ammonium sulphate fractionation 50 155 Second ammonium sulphate fractionation 5 3

Dao 15—25 45—70 90—120

200—250

The final preparation is about 40 times more active than the original

cytochrome c-deficient heart muscle preparation and is over 200 times more active than a heart muscle homogenate.

as can be seen in Fig. 3.

The best preparation obtained, is nearly electrophoretically homogeneous

Fig. 3. Electrophoretic pattern of highly purified succinic dehydrogenase. The solution contained approximately 2 mg/ml of enzyme N, 0.04.M phosphate buffer, pH 7.8 and 0.2 M NaCl. Electrophoresis was carried out with a current of 2 mA, 25 V for 30 minutes, The specific activity of the enzyme material used in this experiment, assayed some time after the electrophoretic run had completed, was 163. Partial air inactivation must have already taken place when the assay was made; the original activity of the enzyme preparation was probably much higher. As mentioned elsewhere in this paper, the electrophoretic pattern is not changed after air inactivation .