libraries generated against the tert-butyl phosphonatehapten 2 and the chloromethyl phosphonatehapten 3 with pivaloyloxymethyl-umbelliferone 1 as a fluorogenic substrate led to the isolation of eleven catalyticantibodies with rate accelerations around kcat/ kuncat = 10(3). The antibodies are not inhibited by the product and accept different acyloxymethyl derivatives of acidic phenols as substrates. The
Fluorescent probes and their salts show sufficient solubility in water and detect sulfane sulfur in vivo. The fluorescent probes can have the following structure: