PubMed Health⌕ Search

Biomedical subjects

J Donaghy

Publications and source records attributed to J Donaghy.

4 recordsLinked to original sources

CASP and CONSORT.

Explore the source record for details and available documents.

Anti-Infective Agents, Local↗

Detection of ferulic acid esterase production by Bacillus spp. and lactobacilli.

The production of feruloyl esterase activity by Bacillus spp. and lactobacilli can be detected in an agarplate assay. The assay involves the substitution of the main carbon source in specific agar with ethyl ferulate. A number of Bacillus spp., predominantly B. subtilis strains, were found to exhibit feruloyl esterase activity by this method. Of the examined lactobacilli, Lb. fermentum (NCFB 1751) showed the highest level of ferulic acid esterase activity. The enzyme was released from harvested cells by sonication and showed pH and temperature optima of 6.5 and 30 degrees C respectively.

Bacillus↗

Purification and characterization of a feruloyl esterase from the fungus Penicillium expansum.

An extracellular phenolic acid esterase produced by the fungus Penicillium expansum in solid state culture released ferulic and rho-coumaric acid from methyl esters of the acids, and from the phenolic-carbohydrate esters O-[5-O-(trans-feruloyl)-alpha-L-arabinofuranosyl]-(1-->3)-O-beta- D-xylopyranosyl-(1-->4)-D-xylopyranose (FAXX) and O-[5-O-((E)-rho-coumaroyl)-alpha-L-arabinofuranosyl]- (1-->3)-O-beta-D-xylopyranosyl-(1-->4)-D-xylopyranose (PAXX). The esterase was purified 360-fold in successive steps involving ultrafiltration and column chromatography by gel filtration, anion exchange and hydrophobic interaction. These chromatographic methods separated the phenolic acid esterase from alpha-L-arabinofuranosidase, pectate and pectin lyase, polygalacturonase, xylanase and beta-D-xylosidase activities. The phenolic acid esterase had an apparent mass of 65 kDa under non-denaturing conditions and a mass of 57.5 kDa under denaturing conditions. Optimal pH and temperature were 5.6 and 37 degrees C, respectively and the metal ions Cu2+ and Fe3+ at concentrations of 5 mmol 1-1 inhibited feruloyl esterase activity by 95% and 44%, respectively, at the optimum pH and temperature. The apparent Km and Vmax of the purified feruloyl esterase for methyl ferulate at pH 5.6 and 37 degrees C were 2.6 mmol 1-1 and 27.1 mumol min-1 mg-1. The corresponding constants of rho-coumaroyl esterase for methyl coumarate were 2.9 mmol 1-1 and 18.6 mumol min-1 mg-1.

Carboxylic Ester Hydrolases↗