Characterisation of feruloyl esterase activity in barley

Feruloyl esterase activity has been detected in barley grain and germinated barley. No differences have been found between the values of activity agai nst methyl ferulate in barley crude extracts (1.05 +/- 0.10 mU mg(-1) prote in) with and without sterilisation (P > 0.05), indicating that the activity is native to the barley grain rather than due to microbial contamination. The highest value of esterase activity was detected after 2 day growth, alt hough an overall downward trend was observed over a 6 day germination perio d at 25 degrees C. The K-m and V-max of the crude barley esterase/s on meth yl ferulate were 0.34 +/- 0.05 mM and 0.76 +/- 0.03 mU mg(-1) protein, resp ectively. The crude extracts were also active upon the methyl esters of sin apic, p-coumaric and caffeic acids, and upon a feruloylated arabino-oligosa ccharide (Ara(2)F), but not upon the methyl ester of vanillic acid. (C) 199 9 Society of Chemical Industry.