PRELIMINARY ELECTROCHEMILUMINESCENCE STUDIES OF METAL ION-BACTERIAL DIAZOLUMINOMELANIN (DALM) INTERACTIONS

Electrochemiluminescence (ECL) studies of the chemiluminescent (CL) po lymer diazoluminomelanin (DALM) biosynthesized in nitrate reductase tr ansfected Escherichia coli JM109 bacteria revealed noteworthy anodic E CL and even more intense cathodic ECL. Bacterial BALM (BD) ECL was als o assessed in the presence of 100 ppm of 33 different metal and non-me tal ions which revealed specific anodic, but not cathodic, enhancement s of ED ECL with Ag+, Hg2+ and Ru3+. The precursors and intermediate p olymers which comprise CALM, such as luminol, 3-amino-L-tyrosine (3-AT ), aminomelanin (AM) and diazomelanin (DM) were screened for ECL enhan cement against the same set of elemental ions. Significant anodic ECL enhancements were observed for luminol with Hg2+ in the presence of tr ipropylamine (TPA), but not for any other DALM component in combinatio n with other elemental ions, either anodically or cathodically. Compar ison of ED with luminol in the presence and absence of TPA and Hg2+ re vealed very different ECL activity patterns and suggested different me chanisms for ED and luminol ECL. (C) 1998 John Wiley & Sons, Ltd.