Acts in defense of young plant parts against pests via the production of hydroxamic acids from hydroxamic acid glucosides. Enzymatic activity is highly correlated with plant growth. The preferred substrate is DIMBOA-beta-D-glucoside. Hydrolysis of terminal, non-reducing beta-D-glucosyl residues with release of beta-D-glucose. DIMBOA beta-D-glucoside + H2O = D-glucose + DIMBOA DIBOA beta-D-glucoside + H2O = D-glucose + DIBOA kcat is 214 sec(-1) with DIBOA-beta-D-glucoside as substrate (with recombinant enzyme). kcat is 1201 sec(-1) with DIMBOA-beta-D-glucoside as substrate (with recombinant enzyme). kcat is 128.2 sec(-1) with p-nitrophenyl beta-D-glucopyranoside as substrate (with recombinant enzyme). Optimum pH is 5.5. Homo- and heterohexamers. Expressed in young seedlings early after germination. Peak of expression 36 to 48 hours after imbibition. Wheat is a hexaploid with three different genomes that contains at least four genes coding for GLU1: GLU1A (AC Q1XIR9), GLU1B (AC Q1XH05), GLU1C (AC Q1XH04) and GLU1D (AC D5MTF8). The monomers can aggregate in diverse combinations, reflecting the several isozymes found in the native enzyme described in PubMed:10750901. The hexameric structure is required for activity toward DIMBOA-beta-D-glucoside (PubMed:16751439). Belongs to the glycosyl hydrolase 1 family.