SYNTHESES AND TESTING OF SUBSTRATES AND MECHANISM-BASED INACTIVATORS FOR XYLANASES

The syntheses of the 2,5- and 3,4-dinitrophenyl beta-xylobiosides by two separate routes are described, as well as the syntheses of the 2,4-dinitrophenyl beta-glycosides of 2-chloro-2-deoxyxylobiose and 2-deoxy-2-fluoro-xylobiose. Both the 3,4- and 2,5-dinitrophenyl beta-xylobiosides proved to be good substrates for the Bacillus subtilis xylanase, with k(cat)/K-m values of 1.0 and 34.4 mM(-1) s(-1), respectively. Excellent time-dependent inactivation of the exoxylanase/glucanase from Cellulomonas fimi was provided by 2,4-dinitrophenyl 2-deoxy-2-fluoro-beta-xylobioside,according to inactivation parameters of k(i) = 0.057 min(-1) and K-i = 0.0035 mM.