Abstract
Two xylanases (XylA and XylE) of glycoside hydrolase family 10 are isolated from an enzyme preparation produced by Penicillium canescens fungi. The kinetics of the hydrolysis of glucuronoxylan and arabinoxylan by the purified enzymes and the effect of proteinaceous (XIP-like) inhibitors from rye on the viscometric activity of the xylanases are studied. XylA provides a more complete conversion of glucuronoxylan than XylE, while XylE is more effective in the arabinoxylan hydrolysis. Unlike XylA, XylE is resistant to the proteinaceous inhibitors from rye—this property is rarely found in the enzymes of family 10. Thus, XylE is a promising enzyme for use as a cereal feed additive, while XylA may potentially be used for the biobleaching of cellulose from hardwoods, which contain glucuronoxylan as one of the major components.