FIG. 8.

pH stability of CDH at 35°C. CDH (0.2 mg) was incubated in an appropriate buffer, and the activity was monitored by DCIP assay. The different buffers used were 50 mM Na-citrate for pHs 3.2 to 5.7 and 20 mM Tris for pH 7.6. Mean values are shown for duplicate experiments; the standard deviations did not exceed 5%. Symbols: pH 3.2 (▴), pH 4.0 (○), pH 5.0 (×), pH 5.7 (●), and pH 7.6 (▵).