Fluorescence Lifetime Measurements of Mercury/Protein Complexes

Abstract

Fluorescence lifetime and steady-state fluorescence measurements are used to characterize various mercury/protein and mercury/protein/EDTA complexes. The proteins studied are ovalbumin, α-chymotrypsinogen, and acid phosphatase. Mercury quenches fluorescence in ovalbumin with a change in lifetime, while in α-chymotrypsinogen quenching occurs without a change in lifetime. No quenching by mercury is observed for acid phosphatase. EDTA causes a further small decrease in fluorescence for both mercury/ovalbumin and mercury/α-chymotrypsinogen, while no change is observed for mercury/acid phosphatase. In all cases the decrease in fluorescence intensity is consistent with a static quenching mechanism. The results reported are correlated to previous studies by bromine-81 magnetic resonance spectroscopy.