2,5-Dimethyl-1,4-benzoquinone is a quinone derivative. Its reaction with jack bean urease in phosphate buffer, pH 7. 8 has been studied. It is present as one of the component of defensive secretion of opilionid Acanthopachylus aculeatus. It has been investigated as inhibitor of jack bean urease in 50mM phosphate buffer, pH 7. 0.