Xylanases inhibitors

Cellulases can also be eliminated fiom a mixture with xylanases by selective thermal inactivation. Cellulases are more thermolabile than xylanases in tiie cdlulolytic systems of the fungus Y-94 (79), T. harzianum 20), and Tkermoascus aurantiacus (77), but not in the Trickoderma reesei system (Biely, P. and Vrsanska, M., Slovak Academy of Sciences, Bratislava, unpublished results). Since cellulase thoixud inactivation causes a significant loss of xylanase also, a more convenient way to eliminate cellulase activity is by selective chemical or biological inhibition or inactivation. There appear, however, to be no reports on the existence of natural inhibitors that would be specific for cellulases. Such inhibitors of amylases and pectinases are known to occur in plants (27). 

Further progress can be expected in the area of selective inhibition and inactivat-iem of cellulases undesirable in xylanase preparations. There is a possibility of finding natural selective cellulase inhibitors or developing highly reactive derivatives of cello-biose and cellodextrins that inactivate cellulolytic enzymes. 

This important concept was rapidly absorbed by the research community, providing fine-tuning of both glycosidase categorization and inhibitor design. In particular, subtle differences of xylosidase and xylanase specificities were probed, and they provided useful insights into the complex and finely tuned enzymatic hydrolysis of glycosides. 

Family 10 xylanase Cex from Cellulomonas fimi and family 11 xylanase Bex from Bacillus circulans198,199 (the first being an anti-, the second a syn-protonator) were exposed to deoxynojirimycin-related (80, Scheme 22) and isofagomine analogous (81) xylosidase inhibitors, along with the anti-protonation-selective xylobiosyl... 

Compound (44 g, NHAc form) (Scheme 14) was found to be a competitive inhibitor for CBHI cellulase (family 7) from Trichoderma reesei, when 4-methyl-umbelliferyl / -lactoside was used as substrate. Therefore (44 g, NHj form) was coupled to CH-Sepharose 4B, and the affinity gel was very effective for the purification of cellobiohydrolases from a crude commercial cellulolytic extract of T. reesei [40c]. Using the same approach aryl 1,4-dithioxylobioside and l,4,4 -trithioxylotrioside (44 h, NH2 form) were coupled to CH-Sepharose 4B to give affinity gels which were used for the purification of xylanases [40a,b]. 

MD simulations of xylanase II from Trichoderma longibrachiatum in mixtures of ILs [emim]OAc or [emim]EtSO and water showed that the enzyme solvated in higher concentrations of ILs generally remains more stable than when solvated in water on the timescales studied. The study indicated that [emim] cation binds strongly in the binding pocket of the enzyme, acting as a competitive inhibitor [118]. 

Bifimctional inhibitor of xylanase and asp>artic proteases from extremophilic microorganism Bacillus sp. asp>artic proteinase inhibits HIV-1 (Dash et al., 2001). 

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