Various methods for the immobilization of urease and butyrylcholinesterase on the insulator surface of a laser-scanned semiconductor transducer (LSST) have been tested and compared for the development of an enzyme-based light-addressable potentiometric sensor (LAPS). The method of preparing photocurable membranes on LAPS is presented, and a new type of enzyme LAPS with photocurable polymeric enzyme membranes has been elaborated. It was found that sensors prepared by means of covalent bonding and cross-linking with inactive protein (type SIII) and with photocurable membrane matrices (type SIV) are more prospective. The enzyme LAPSensors with photocurable membranes demonstrate a degree of sensitivity close to the theoretical value and working ranges of 6.3.10(-5)-1.1.10(-2) and 1.10(-4)-1.10(-1) mol L-1 urea for acrylamide and acrylate-based membrane matrices, respectively, and 2.5.10(-4)-2.10(-1) mol L-1 butyrylcholine for an acrylamide membrane matrix. It is shown that such sensors can be also used for the analysis of enzyme inhibitors.