Post-translational processing of beta-d-xylanases and changes in extractability of arabinoxylans during wheat germination.

Endo-1,4-beta-d-xylanase (EC 3.2.1.

Unprocessed barley aleurone endo-beta-1,4-xylanase X-I is an active enzyme.

Endo-beta-1,4-xylanase X-I is a major hydrolase produced by the aleurone tissue of germinating barley grain. It was previously reported that this cytosolic enzyme is synthesized as an inactive precursor which is proteolytically processed to active forms upon its programmed cell death dependent release. We here demonstrate, however, that the precursor form of X-I is an active enzyme.