Phosphorothioates, analogues of phosphate esters in which a sulfur replaces an oxygen atom in the phosphoryl group, are competent surrogate substrates for a number of phosphatases. In some cases the thio analogues show similar binding (as estimated by K m) while other phosphatases show quite different K m values for phosphate compared to phosphorothioate esters. On this basis it was hypothesized that there might be different ...
