1887

Abstract

An inducible ferulic acid esterase (FAE-III) has been isolated, purified and partially characterized from after growth on oat spelt xylan. The purification procedure utilized ammonium sulphate precipitation, hydrophobic interaction and anion-exchange chromatography. The purified enzyme appeared almost pure by SDS-PAGE, with an apparent of 36000. A single band, corresponding to a pl of 3·3 was observed on isoelectric focusing. With methyl ferulate as substrate, the enzyme had a specific activity of 67 IU (mg protein), pH and temperature optima of 5 and 55–60 °C, respectively, and a m of 2·08 mM and a of 175 μmol min (mg protein). The enzyme was also active upon methyl sinapinate, methyl-3,4-dimethoxy cinnamate and methyl -coumarate, but not benzoic acid methyl esters or methyl caffeate. Similarly, FAE showed activity against methyl ferulate, methyl sinapinate and methyl -coumarate, but at a level 420-fold less (on methyl ferulate) than the esterase. No activity was detected against the benzoate methyl esters. For both enzymes, this shows the necessity for C-3 on the phenol ring to be methoxylated and the aliphatic region of the substrate to be unsaturated. The specific activity of FAE-III on destarched wheat bran was 31 U (mg protein) in the presence of xylanase and 3 U (mg protein) in the absence. Apparent pH dependent binding of FAE-III to microcrystalline cellulose was also demonstrated.

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/content/journal/micro/10.1099/00221287-140-4-779
1994-04-01
2019-11-12
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http://instance.metastore.ingenta.com/content/journal/micro/10.1099/00221287-140-4-779
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