AMINE-REACTIVE FORMS OF A LUMINESCENT DIETHYLENETRIAMINEPENTAACETIC ACID CHELATE OF TERBIUM AND EUROPIUM - ATTACHMENT TO DNA AND ENERGY-TRANSFER MEASUREMENTS

An isothiocyanate form of a lanthanide chelate which is highly lumines cent when bound to terbium or europium has been synthesized. The chela te consists of diethylenetriaminepentaacetic acid (DTPA) covalently jo ined to a chromophore, 7-amino-4-methyl-2(1H)-quinolinone (cs124), and to L-p-aminophenylalanine, in which the aromatic amine was further co nverted to an isothiocyanate group. Ethylenediamine was also used in p lace of aminophenylalanine, but the isothiocyanate formed from the ali phatic amine was significantly less reactive. Site-specific attachment s to triglycine and to the 5' ends of amine-modified DNA oligomers hav e been made. In addition, as an alternative method of coupling to macr omolecules, DTPA anhydride-cs124 can be used to react specifically wit h a 5' amine group on base-deprotected synthetic DNA oligomers. Synthe sis and purification is relatively straightforward in both cases, and luminescent properties are favorable for several applications, includi ng as nonisotopic labels, as long-lifetime alternatives to fluorophore s in imaging and diagnostics and particularly as donors in luminescenc e resonance energy transfer. Energy transfer measurements are consiste nt with previously reported measurements using different attachment me chanisms.