Regulation of cell wall glucanase activities by non-enzymic proteins in maize coleoptiles

Auxin stimulates cell wall glucanase activities in isolated segments of maize coleoptiles with no detectable change in the amounts of the enzymic peptides. To disclose the regulatory mechanism for this enhanced growth, we examined the possibility that protein interactions account for stimulating cell wall enzyme activities. One putative regulatory peptide, an acidic wall protein (AW), was separated from the wall protein fractionation profile, and this non enzymic protein was able to stimulate both exo- and endoglucanase activities in vitro. The results are consistent with the hypothesis that a pertinent glucanase/glucan interaction might be facilitated by AW mobilization within the wall in response to auxin-treatment.