Regulation and Partly Purification of the ATP-Sulfurylase from the Cyanobacterium Synechococcus 6301

ATP-sulfurylase from the cyanobacterium Synechococcus 6301 was regulated in vivo during growth in batch culture. The activity was highest at the third day after inoculation, declining afterwards to a level found in resting cells. During growth with air supplemented with 2% CO2 this activity increased 3-fold compared to controls grown with normal air as CO2 source. Addition of either nitrite or urea enhanced ATP-sulfurylase activity about 2-fold, whereas cysteine and especially methionine decreased ATP-sulfurylase activity to 5% of controls without treatment. The ATP-sulfurylase was purified by conventional techniques using DEAE-cellulose chromatography and further separation on blue sepharose achieving a 250-fold increase in the specific activity. An apparent Kᴍ of 5 μᴍ for APS and of 40 μᴍ for pyrophosphate was determined with the purified enzyme fraction.