Sulphate is a competitive inhibitor of the binding of nucleotide to myosin. A comparison with phosphate

By the use of rapid reaction methods (rapid flow quench and stopped flow) it has been shown that sulphate is a competitive inhibitor of the binding of epsilon-ATP and ATP to myosin. At low ionic strengths, the Ki was in the micromolar range. Under several conditions used sulphate was more effective than phosphate. Neither anion was very effective in inhibiting the binding of epsilon-ATP to actomyosin.