protein purification & imidazole problems

[Chris McDermott-Roe]

Hi all,

I've expressed a recombinant protein in E.coli, purified it via Ni-NTA
chromatography and am now attempting to measure its potential inhibitory
activity in a fluorescence assay that involves excitation at 485 nm and
measurement at 530 nm.  The problem is that my protein prep is giving a huge
signal (as is my buffer alone control) which makes me think the imidazole
(which is present in the elution buffer) is fluorescing.  Does anybody have
any experience with this kind of thing?

Cheers

Chris