Can you specify which enzyme(s) you wish to assay and what technologies are available to you (spectrophotometer, fluorometer, HPLC, plate reader, mass spec, etc)? Do you need a high-throughput method? Do you need a continuous assay?

Hi Adriana, as Adam said, you have to specify which enzyme you are looking at because there a lot of hydroxylases out there.

And each one might require a different set of assay conditions.