Berglund:Materials

10x yeast pyrophosphatase
50% glycerol 10mM HEPES-KOH pH 7.5 6mM MgCl2

120µg yeast pyrophosphatase from Sigma i1891 (0.01U/µl)= 120U lyophilized and would be diluted into a fv=12ml But, you may receive less than 120µg and so you dilute accordingly (100µg =100U= fv of 10ml for 10x stock)