Detection of neuraminidase activity in Pseudomonas aeruginosa PAO1

Some properties of neuraminidase produced by Pseudomonas aeruginosa PAO1 growth in a defined medium
(BHI) were examined and evaluated for its features.
Materials and Methods
The 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.
Results
Among 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.
Conclusion
Overall, the results indicated that neuraminidase of P. aeruginosa PAO1 is more an extracellular enzyme
than K. pneumonia neuraminidase is.