Arabinoxylan Hydrolases

In aqueous extracts of wheat flour, arabinoxylan hydrolases have been detected with the synthetic 

Substrate Relative activity (%) Kinetic constants Vm (nkat/ml) Km (mmol/1) 

Structures of the corresponding ascorbic acid diastereomers, cf 15.4.1.4.1. Concentration of GSH 3 mmol/1. n.a. not analyzed. 

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Ferulic acid is ubiquitously present in plants, mainly as part of the cell walls esterified to polysaccharides such as arabinoxylans. It is also an intermediate in the secondary metabolism of phenylalanine and tyrosine. It can be conveniently isolated from corn hulls, rice bran, and sugar beet. Biocatalytic processes using cinnamoyl esterases and glycosyl hydrolases have been developed for this purpose [32]. Another potentially interesting source is lignin, since ferulic acid is one of the prominent byproducts of its degradation. 

Vandermarliere, E Bourgois, TM Winn, MD Van Campenhout, S Volckaert, G Delcour, JA et al. Structural analysis of a glycoside hydrolase family 43 arabinoxylan arabinofuranohydrolase in complex with xylotetraose reveals a different binding mechanism compared with other members of the same family. Biochem J., 2009, 418, 39-47. 

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