Glucanases specificities

Endo-1,4-3-glucanase (specific, non-hydrolyzing xylan, but hydrolyzing 3-cellobiosides and 3-lactosides) OBR-HEC, Umb-Gz, Umb-L... 

Hehre and coworkers showed that beta amylase from sweet potatoes, an inverting, a-specific exo-(l 4)-glucanase, catalyzes the hydrolysis of jS-maltosyl fluoride with complex kinetics which indicated the participation of two substrate molecules in the release of fluoride ion. Furthermore, the reaction was strongly accelerated by the addition of methyl ) -maltoside. Hydrolysis of a-maltosyl fluoride, on the other hand, obeyed Michaelis-Menten kinetics. The main product with both a- and yj-maltosyl fluoride was )S-maltose. The results with )3-maltosyl fluoride were interpreted by the assumption of a glycosylation reaction preceding hydrolysis by which a malto-tetraoside is formed by the replacement of fluoride ion by a second substrate molecule or added methyl -maltoside (see Scheme 5). 

M. Faijes, X. Perez, O. Perez, and A. Planas, Glycosynthase activity of Bacillus licheniformis 1,3-1,4-beta-glucanase mutants Specificity, kinetics, and mechanism, Biochemistry, 42 (2003) 13304—13318. 

When T. harzianum IMI298372 was grown on cell walls of R. solani as carbon source, electrophoresis showed that a much more complex mixture of extracellular proteins was formed when the antagonist was grown on glucose (28). While both 1,3-/ -D glucanase and chitinase were induced, irrespective of whether glucose or cell walls were used as the carbon substrate, the total activity and specific activity depended on the substrate (Table II). 

J.K. Fairweather, M. Faijes, FI. Driguez, A. Planas, Specificity studies of bacillus 1,3-1,4-beta-glucanases and application to glycosynthase-catalyzed transglycosylation, Chembiochem 3 (2002) 866-873. 

Keefe, D., Hinz, U. Meins, F. (1990). The effect of ethylene on the cell-type-specific and intracellular localization of P-1,3-glucanase and chitinase in tobacco leaves. Planta 182, 43-51. 

LPS also has effects on cell wall alterations such as callose deposition (Keshavarzi et al., 2004) and on PR gene induction (Zeidler et al., 2004 Silipo et al., 2005). In some cases specific effects of a particular LPS on plant gene induction are observed. LPS from the crucifer pathogen Xcc induced expression of a gene encoding a defense-related (->-(1 -3) glucanase when applied to turnip leaves at 1 p,g per ml. In contrast, LPS from Escherichia coli and Salmonella enterica were ineffective at concentrations up to 50 p,g per ml (Newman et al., 1995). Such specific effects may reflect the ability of particular plants to recognize structural features within LPS that are not widely conserved. 

Kim, C. H., Characterization and substrate specificity of an endo-beta-l,4-D-glucanase I (Avicelase I) from an extracellular multienzyme complex of Bacillus circulans. Appl Environ Microbiol 1995, 61 (3), 959-65. 

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