Europium and terbium chelators for the time-resolved fluorometric assays
AssigneeNordion International Inc.
InventorEleftherios P. Diamandis
Life of this patent
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Abstract
Fluorogenic chelators for Eu.sup.3+ and Tb.sup.3+ are provided, they form highly fluorescent complexes with Eu.sup.3+ and Tb.sup.3+. In all cases, the fluorescence observed was lanthanide-specific, long-lived and it was monitored by microsecond time-resolved fluorometry. The fluorogenic chelators could be quantified, in the presence of excess lanthanide, at levels<10.sup.-8 mol/L. Fluorogenic chelators can form ternary complexes with Eu.sup.3+ and Tb.sup.3+, in the presence of EDTA. The structures of the identified chelators is such that enzyme substrates can be used for enzyme-labelled time-resolved fluorometric immunoassays.
Claims11
In a time resolved fluorometric assay comprising the steps of:
- enzymatically treating a substrate to form a fluorescent lanthanide metal chelate in the presence of a lanthanide metal ion and detecting the fluorescence emitted, the improvement comprising forming a fluorescent lanthanide metal chelate between either Eu.sup.3+ or Tb.sup.3+ and an enzymatically treated substrate selected from the group consisting of:
- 3-hydroxypicolinic acid;
- 4-hydroxy-7-methyl-1,8-naphthyridine-3-carboxylic acid;
- 3-hydroxy-2-quinoxaline carboxylic acid;
- 7-hydroxycoumarin-4acetic acid;
- calcein blue;
- 2-quinoxaline carboxylic acid;
- pterin-6-carboxylic acid;
- and 4methylumbelliferyl phosphate.
In a time-resolved fluorometric assay, comprising the steps of:
- enzymatically treating a substrate to form a lanthanide metal chelate in the presence of a lanthanide metal ion and detecting the fluorescence emitted, the improvement comprising the use of a substrate from the group consisting of those with the following formulae II, IV, V, VI, VII, VIII, IX, and X:
- ##STR2##
In a time resolved fluorometric assay, comprising the steps of:
- enzymatically treating an ester of a substrate to form a lanthanide metal chelate in the presence of a lanthanide metal ion to render the lanthanide metal chelate as either fluorescent or non-fluorescent when combined with the lanthanide metal and detecting the fluorescence emitted, the improvement comprising the use of an ester of a substrate of any of the following formulae II, IV, V, VI, VII, VIII, IX and X:
- ##STR3##
Dependencies are inferred from the claim text.