CONJUGATES OF A CEPHALOSPORIN DERIVATIVE AND A FLUOROPHOR PRECURSOR AND RELATED COMPOUNDS AS SUBSTRATES FOR BETA-LACTAMASE GENE EXPRESSION

摘要

Fluorescent substrates for beta-lactamases having the general formula shown above are provided. Z includes a fluorophore or chromophore and includes a group that may link to the lactam-containing group; R₁ and R₂ are independently selected from H, aliphatic, aromatic, alkyl, and acyl ; R₄ may be H and lower alkyl; B may be H, physiologically acceptable salts or metal, ester groups, ammonium cations, --CHR₅OCO(CH₂)_nCH₃, --CHR₅OCOC(CH₃)₃, acylthiomethyl, acyloxy-alpha-benz, deltabutyrolactonyl, mehtoxycarbonyloxymethyl, phenyl, methylsulphinylmethyl, beta-morpholinoethyl, dialkylaminoethyl, and dialkylaminocarbonyloxymethyl, in which R₅ is selected from the group consisting of H and lower alkyl; n is an interger between 0 and 10, inclusive; and A may be S, O, SO, SO₂, or CH₂. In embodiments, the beta-lactam ring may be cleaved by a beta-lactamase enzyme effective to free a fluorophore. Methods of assaying beta-lactamase activity and monitoring expression in systems using beta-lactamase as a reporter gene are also disclosed.