Fluorescence of phosphotyrosine--terbium(III) complexes.
Phosphotyrosine, a biologically important protein residue, was investigated for the ability to enhance terbium (Tb3+) fluorescence. Spectroscopic analysis of the Tb3+: phosphotyrosine interaction indicated the development of a new excitation peak at 275 nm and strong Tb+ fluorescence enhancement at 488 and 540 nm that was linear over a range from 0.5 to 100 microM amino acid. Subsequent experiments comparing the ability of phosphotyrosine, phosphothreonine, phosphoserine and 20 other common non-phosphorylated amino acids showed that only phosphotyrosine produced significant Tb3+ fluorescence enhancement. Analysis of various phospho-sugars and nucleotides showed (with the expected exception of GMP) that they produced little or no significant fluorescence enhancement, indicating a further selectiveness for the phosphotyrosine: Tb3+ fluorescence enhancement event. These results establish a basis for the future use of Tb3+ fluorescence enhancement as a unique probe for the investigation of phosphotyrosine residues.
Samuel Roberts Noble Foundation, Inc. Ardmore, Oklahoma 73402.
D P
DP
Ringer
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Etheredge
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Dalrymple
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JS
Niedbalski
D066298:In Vitro Techniques; D010766:Phosphorylation; D019000:Phosphotyrosine; D011485:Protein Binding; D013050:Spectrometry, Fluorescence; D013725:Terbium; D014443:Tyrosine / Q000031:analogs & derivatives*
D013725:Terbium; D019000:Phosphotyrosine; D014443:Tyrosine