Enzymic Profiling of Immobilized Cells Using CZE

Baker's yeast cells (Saccharomyces cerevisiae) were immobilized on a CZE capillary using a midcapillary frit of novel design. The frit was constructed using a single 50-microns particle with "through pores". Cells trapped on the capillary were profiled using different amino acid beta-naphthylamide-aminopeptidase substrates. These substrates were introduced sequentially and metabolized for 1 min. After incubation the hydrolysis products were withdrawn by electrophoresis and detected by laser-induced fluorescence. An aminopeptidase profile was produced using just 500 cells. The new CZE-based method was found to have several significant advantages over the older cuvette/fluorometer method.