ATP-Sulfurylase From Penicillivm Chbysogenum. I. Purification and Characterization

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Abstract
ATP-sulfurylase (ATP-sulfate adenylyl transferase, EC. 2.7.7.4) from Peniaillium ehrysogenum has been purified 945-fold by a procedure involving heat treatment, ammonium sulfate fractionation, anion exchange chromatography, and gel filtration. The overall recovery of activity was 47%. The puirified protein is homogeneous by the criteria of disc gel electrophoresis, gel filtration, and analytical ultracentrifugation. The specific activity of the purified enzyme, when assayed using molybdate as the substrate is 3β μmole Pi-min−1 -mg−1. The enzyme requires a divalent cation for activity (Mg2+ Mn2+ or Co2+). The best nucleoside triphosphate substrate for the enzyme is ATP4. The stoichiometry of the reaction with molybdate as substrate is: . The reaction in the reverse direction is : . The pH optimum for the enzyme is broad with maximum activity between pH 7.5 and 9.0. The enzyme is stable at temperatures up to 50o and exhibits a Q10. of 1.85 between 30° and 40o. The absorbancy of the purified protein ( ) at 278 mμ is 8.71. The molecular weight of the enzyme is 420,000 to 440,000. In the presence of SDS subunits with a molecular weight of about 56,000 are observed.