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% CO, this activity increased 3-fold compared to controls grown with normal air as C 0 2 source. Addition o f either nitrite or urea enhanced ATP-sulfurylase activity about 2-fold, whereas cys­ teine and especially methionine decreased ATP-sulfurylase activity to 5% o f controls without treatment. The ATP-sulfurylase was purified by conventional techniques using DEAE-cellulose chro­ matography and further separation on blue sepharose achieving a 250-fold increase in the spe­ cific activity. An apparent o f 5 for APS and o f 40 |iM for pyrophosphate was deter­ mined with the purified enzyme fraction.