Becton Dickinson and Company Limited

J Michael Quante

Daniel L Woodard

Randal A Hoke

Patrick D Mize

O Elmo Millner, Deceased

Chromogenic and fluorogenic substrates for .beta.-lactamase, methods for synthesis thereof and methods for detecting .beta.-lactamase in a sample are provided. The substrates are substantially colorless or substantially nonfluorescent .beta.-lactam compounds which include an electronegative leaving group. The leaving group comprises a carbamate, carbonate, thiocarbamate or thiocarbonate linkage and a fluorescent moiety or a moiety capable of producing a visually detectable colored product. Upon cleavage of the lactam ring by .beta.-lactamase, the leaving group is liberated and fluorescence or a colored product is produced.

Fluorogenic and chromogenic .beta.-lactamase substrates

Process for preparing cephalosporin compounds

A method for enzyme immunoassay includes contacting under binding conditions a liquid suspected of containing an analyte, an antianalyte and a tracer having conjugated thereto delta 5-3-ketosteroid isomerase. A bound fraction is separated from the liquid and incubated in a second liquid with a delta 5-3-ketosteroid substrate. Isomerase on the bound fraction converts the substrate to the corresponding delta 4-3-ketosteroid. A tetrazolium salt and a base are added. Unconverted delta 5-3-ketosteroid reduces the tetrazolium salt to a formazan which imparts a color to the liquid. A signal associated with the color may be used to detect or to measure the concentration of the analyte in the liquid. The invention includes a kit of materials useful in performing the assay of the invention.

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Durham, NC, United States of America

J Michael Quante