... was a mixture of 0.05 M NaPi buffer, pH 3, and acetonitrile (6 : 1, v/v); separation was performed isocratically, at a flow rate of mLÆmin)1, and the volume of injected samples was 10 lL The amounts ... concentration of both the assayed compound and its respective transformation product was determined by comparison of peak data with those obtained from authentic standards chromatographed at different ... Extraction and purification of F 4¢-OMT All the purification steps were carried out at °C temperature The enzyme was concentrated at various steps of purification using collodion bags with kDa cut-off...