Catalyzes the synthesis of activated sulfate. Essential for plant reproduction and viability. Required for the production of glucosinolates. adenosine 5'-phosphosulfate + ATP = 3'-phosphoadenylyl sulfate + ADP + H(+) Sulfur metabolism; hydrogen sulfide biosynthesis; sulfite from sulfate: step 2/3. Homodimer; disulfide-linked. Interacts with APK2. Expressed in root vasculature, root tips, leaf epidermal and guard cells, pollen grains and funiculus of developing seeds. No visible phenotype under normal growth conditions. Apk1 and apk2 double mutant exhibits a semi-dwarf phenotype. Belongs to the APS kinase family.