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An enzyme from Auricularia auricula-judae combining both benzoyl and cinnamoyl esterase activity
- Haase-Aschoff, Paul, Linke, Diana, Nimtz, Manfred, Popper, Lutz, Berger, Ralf G.
- Process Biochemistry 2013 v.48 pp. 1872-1878
- Auricularia, anion exchange chromatography, benzoates, benzoic acid, cinnamates, databases, feruloyl esterase, fungi, glycerol, hydrophobic interaction chromatography, isoelectric focusing, isoelectric point, long chain fatty acids, methyl salicylate, molecular weight, p-nitrophenol, pH, peptides, proteins, sequence homology, substrate specificity, temperature
- Benzoic acid esterases and ferulic acid esterases (FAE) are enzymes with different profiles of substrate specificity. An extracellular esterase (EstBC) from culture supernatants of the edible basidiomycete fungus Auricularia auricula-judae was purified by anion exchange chromatography, followed by preparative isoelectric focusing and hydrophobic interaction chromatography. EstBC showed a molecular mass of 36kDa and an isoelectric point of 3.2 along with broad pH and temperature windows similar to fungal FAEs. However, EstBC exhibited also characteristics of a benzoic acid esterase acting on both benzoates and cinnamates, and most efficiently on methyl and ethyl benzoate, methyl 3-hydroxybenzoate and methyl salicylate. Feruloyl saccharides as well as lipase substrates, such as long chain fatty acids esterified with glycerol, polyethoxylated sorbitan and p-nitrophenol were not hydrolyzed. Protein database analyses with tryptic peptides of EstBC solely yielded hits regarding hypothetical proteins belonging to the alpha/beta hydrolase family. The uncommon substrate specificity of EstBC concomitant with a lack of sequence homology to known enzymes suggests a new type of enzyme.