Injection volumes of 2 μL were used and a DAD detector recorded absorbance at 210, 220 and 254nm. Substrates and products were eluted over 2 or 4 minutes using a gradient of 20 -95% acetonitrile (0.1% TFA) at 0.8 mL min -1 . Peaks were assigned by comparison to chemically synthesized standards or analysis of MS data and the peak areas were integrated using Agilent OpenLab software.