Compositions, methods and kits for labeling proteins and uses in reporter systems for detecting, quantifying and/or characterizing analytes.

Compositions, methods and kits for labeling proteins and uses in reporter systems for detecting, quantifying and/or characterizing analytes.

Two rhodamine reversible fluorescent sensor derivatives, L.sub.1 and L.sub.2, bearing 2-methoxy-1-naphthaldehyde and 5-bromo-3-methoxy salicylaldehyde units were synthesized using microwave-assisted organic synthesis and used for selective and sensitive reversible sequential fluorescence detection of aluminum ion (Al.sup.3+) and azide (N.sup.3) in aqueous acetonitrile solution via the fluorescence spectral changes. Stoichiometry and binding mechanisms for both sensors are well characterized and established by the respective spectroscopic techniques. L.sup.1 and L.sup.2 sensors are useful for the analysis of Al.sup.3+ and N.sup.3 in environmental samples and biological studies.

Two rhodamine reversible fluorescent sensor derivatives, L.sub.1 and L.sub.2, bearing 2-methoxy-1-naphthaldehyde and 5-bromo-3-methoxy salicylaldehyde units were synthesized using microwave-assisted organic synthesis and used for selective and sensitive reversible sequential fluorescence detection of aluminum ion (Al.sup.3+) and azide (N.sup.3) in aqueous acetonitrile solution via the fluorescence spectral changes. Stoichiometry and binding mechanisms for both sensors are well characterized and established by the respective spectroscopic techniques. L.sup.1 and L.sup.2 sensors are useful for the analysis of Al.sup.3+ and N.sup.3 in environmental samples and biological studies.

A novel amino acid derivative is provided, wherein the amino acid derivative is expected to improve binding affinity of polypeptides comprising the derivative therein.

A novel amino acid derivative is provided, wherein the amino acid derivative is expected to improve binding affinity of polypeptides comprising the derivative therein.