Major beta-glucosidase activating oleuropein into a potent protein cross-linking agent (PubMed:25697790, PubMed:28483880). No activity with rutin, luteolin or p-nitrophenyl-beta-glucopyranoside as substrates (PubMed:25697790). H2O + oleuropein = D-glucose + oleuropein aglycone Optimum pH is 5.5. Optimum temperature is 37 degrees Celsius. Homomultimer. Native form of the enzyme requires at least an octamer conformation. Distinctive compartmentalization of the oleuropein/OeGLU dual partner is a requisite to ensure a correct defense system response and to prevent the autotoxicity. Expressed in expanding leaves and in young drupes, mostly in the developing seed coat tissues, the perisperm and the mesocarp. Also detected in shoot and root meristems, flower buds, developing ovaries and tapetal cells of the anther. Not detected in embryos or endosperm, or in leaf trichomes. Expressed in the developing mesocarp from 13 weeks after flowering until veraison, when the color of drupes turned from green to black. Belongs to the glycosyl hydrolase 1 family.