FIBER OPTIC BIOSENSOR FOR CO(II) AND CU(II) BASED ON FLUORESCENCE ENERGY-TRANSFER WITH AN ENZYME TRANSDUCER

We have demonstrated that fluorescence energy transfer may be made the basis of a zinc biosensor employing carbonic anhydrase as the recogni tion element, or transducer. Herein we describe the use of carbonic an hydrase in a biosensor for Cu2+, and Co2+ using a different transducti on scheme. In particular, we have exploited the well-known d-d absorba nce bands exhibited by these ions when bound in the active site as ene rgy transfer accepters for suitable fluorescent donors. Binding of the metal ion to the apoprotein results in fluorescence quenching and con comitant reduction of the lifetime, which can be related to fractional occupancy of the binding site and thus concentration of the metal ion .