Scientia Sinica

SCIENTIA SINICA

y 10 20 Substrate concentration, mM

Fig. 4A. Effect.of succinate concentration on the activity of succinic dehydrogenase. Curve |: Reaction mixture contained 80 mM phosphate buffer pH 7.8, 5.2 mM potassium ferricyanide, the required concentration of succinate and 0.061 mg enzyme N in a total volume of 4 ml. Temperature 38°C, reaction time 2.5 min. Curve 2: The same reaction mixture except that the enzyme concentration used was 0.108-mg enzyme WN; the temperature, 0°C, and the reaction time, 10 minutes. The enzyme preparation had a specific activity of 76,

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Fig. 4B. Effect of succinate concentration on the activity of succinic dehydrogenase. Data in Fig. 4A plotted according to Lineweaver and Burk, The velocity (v) of the reaction is expressed as decrease of optical density (—Ad).

Vol.

V