Binding affinity testing by fluorescence titration - (Dec/13/2013 )

Dear,

Recently I am trying to use fluorescence titration to understand the interaction of cofactor with enzyme. I was told that the binding of cofactor with enzyme increases absorbance intensity. But when I measured with my enzyme, the intensity indeed is higher than that of cofactor itself at low concentration, but the trend changes at higher concentration (see in picture).

Could you give some suggestions about my results? Many thanks in advance!

Cheers,

Bio

waiting for the response