Buffer D is 20 mM HEPES-KOH (pH 7.9), 20% glycerol (vol/vol), 0.2 mM EDTA, 0.1 M KCl, 0.5 mM phenylmethylsulfonyl fluoride (PMSF), 1 mM DTT. Add PMSF and DTT just before use. The amounts of ...