Detection of Neuraminidase Activity in Pseudomonas aeruginosa PAO1

Objective(s)Some properties of neuraminidase produced by Pseudomonas aeruginosa PAO1 growth in a defined medium (BHI) were examined and evaluated for its features.Materials and MethodsThe obtained supernatant enzyme of P. aeruginosa PAO1 cultures was used in a sensitive fluorometric assay by using 2'-(4-methylumbelliferyl) α-D-N acetylneuraminic acid as substrate. As hydrolyzing MUN with neuraminidase; free N-acetylneuraminic acid and 4-methylumbelliferone were formed with a shift in the fluorescence spectra from 315/374 nm (substrate) to 365/450 nm (product). Enzyme activity was then measured by the fluorescence of 4-methylumbelliferone at 450 nm.ResultsAmong the culture media to determine the enzyme production, the highest production of P. aeruginosa PAO1 neuraminidase was found in BHI culture media. Neuraminidase production in P. aeruginosa PAO1 paralleled bacterial growth in defined medium (BHI) and was maximal in the late logarithmic phase of growth but decreased during the stationary phase, probably due to protease production or thermal instability. The neuraminidase of P. aeruginosa PAO1 possessed an optimum temperature of 56 °C and the activity was pH-dependent with maximal activity at pH 5. Heating the enzyme at 56 °C for 45 min in the presence of bovine serum albumin destroyed 33.1% of the activity while the addition of Ca+2, EDTA and N-acetyl neuraminic acid (NANA) decreased activity markedly. ConclusionOverall, the results indicated that neuraminidase of P. aeruginosa PAO1 is more an extracellular enzyme than K. pneumonia neuraminidase is.