Rapid data acquisition from a microtiter plate fluorescence reader and applications in kinetic measurements

Programs written in Applesoft BASIC for the rapid acquisition and evaluation of data from a commercially available microtiter plate fluorescence reader are presented. Using the data acquisition program, the relative fluorescence readings from all 96 wells of the microtiter plate (one read cycle of the fluorescence reader) can be stored in each of up to 90 consecutively numbered files on a single-sided diskette. A simple timer circuit is described which, when used in conjunction with the above program, initiates the fluorescence reading process at preset time intervals, thus making automatic acquisition of data possible. A further program plots the data from consecutive files on the computer monitor and prints a hard copy if required. The feasibility of applying the above system and software to kinetic measurements in enzyme systems is demonstrated using methylumbelliferyl phosphate and an alkaline phosphatase/immunoglobulin conjugate. In addition, its use in following the formation of extracellular hydrogen peroxide by stimulated polymorphonuclear leukocytes using horseradish peroxidase-coupled oxidation of the fluorescent compound 7-hydroxy-6-methoxy-coumarin (scopoletin) is described.