Enhanced instrumental sensitivity and selectivity for aminopeptidase profiling

Laser-excited fluorimetry has been applied to the identification of bacteria and fungus. The instrumental sensitivity and selectivity of the aminopeptidase profiling method has been enhanced by the use of laser excitation in conjunction with improved spectral and temporal background rejection. The linear dynamic range for the aminopeptidase technique has been increased by achieving a reduced lower limit of detection of the fluorescent tag, beta-naphthylamine. Standard aminopeptidase methodology only provides a linear dynamic range of 1.5 orders of magnitude. The laser-based method expanded the range to three orders of magnitude allowing the inherent specificity of aminopeptidase enzymes within the pathogen to be observed. The enhanced linear dynamic range was observed in profiles of Agrobacterium tumefaciens rubi and Phytophthora megasperma var. sojae.