Cultural conditions of arylsulfatase activity in Escherichia coli

Arylsulfatase activity and growth were estimated in Escherichia coli, isolated from marine sediment. Maximum activity was observed at pH 6.6 whereas the maximum growth was at pH 5.6. 2x10ˉ³ M is the optimum substrate concentration for the highest level of enzyme activity/synthesis as well as for its growth. In general higher substrate concentration tended to inhibit enzyme activity and also the growth of the bacterium. Maximum growth and highest enzyme activity occurred at 29°C and above this temperature decreased both of them. Besides these, glucose, sodium sulfate, sodium chloride, sodium dihydrogen phosphate, sodium acetate and ammonium chloride at higher concentrations were inhibiting the enzyme activity and growth. Above 0.2% of glucose, 3% of sodium chloride, 10x10ˉ³ M concentrations of sodium sulfate, sodium dihydrogen phosphate, sodium acetate and ammonium chloride inhibited the activity and growth also. These observations indicate that, to generalize a compound as inhibitor or activator it is difficult since this depends not only on its concentration but also on the source of the enzyme when more than one type is encountered in nature.