PURIFICATION AND PARTIAL CHARACTERIZATION OF 2 FERULOYL ESTERASES FROM THE ANAEROBIC FUNGUS NEOCALLIMASTIX STRAIN MC-2

Two extracellular feruloyl esterases (FAE-I and FAE-II) produced by the anaerobic fungus Neocallimastix strain MC-2 which cleave ferulic acid from OF-{5-OF-[(E)-feruloyl]-alpha-L-arabinofuranosyl}-(1-->3)-OF-beta-D-xylopy-ranosyl-(1-->4)-D-xylopyranose (FAXX) were purified. The molecular masses of FAE-I and FAE-II were 69 and 24 kDa, respectively, under both denaturing and nondenaturing conditions. Apparent K(m) and maximum rate of hydrolysis with FAXX were 31.9 muM and 2.9 mumol min-1 mg-1 for FAE-I and 9.6 muM and 11.4 mumol min-1 mg-1 for FAe-II. FAE-II was specific for FAXX, but FAE-I hydrolyzed FAXX and PAXX, the equivalent p-coumaroyl ester, at a maximum rate of metabolism ratio of 3:1.