Micellar electrokinetic chromatography for analyzing active site specificity of Pseudomonas aeruginosa elastase

The geometry of the catalytic site of Pseudomonas aeruginosa elastase was r eexamined, exploiting the specific feature of micellar electrokinetic chrom atography (MEKC), i.e., its ability to detect a decrease of intact substrat e and simultaneous formation of reaction products. We carried out a detaile d investigation using two tri- and six tetra-peptide 4-nitroanilides (NA) d iffering from each other by only one or more amino acids as stable substrat es. The kinetic cleavage parameters K-m and k(cat) determined by MEKC and t he catalytic efficiency K-m/k(cat) values calculated allowed us to better d efine the substrate specificity of this proteinase.