Sulfotransferase that utilizes 3'-phospho-5'-adenylyl sulfate (PAPS) as sulfonate donor to specifically catalyze the sulfate conjugation of flavones and flavonols. Strictly specific for the position 7. Substrate preference is kaempferol 3-sulfate > isorhamnetin > kaempferol. Optimum pH is 7.5. Expressed in inflorescence stems, roots and siliques. Expressed mostly in 5-day old seedlings, at developmental stage 1. Up-regulated by trans-zeatin, but not by cold, heat, hypoxia, salt stress, auxins, gibberellins, wounding, etiolation and salicylic acid or methyl jasmonate treatments. Belongs to the sulfotransferase 1 family.