Abstract: In a method of preparing the enzyme, urease, from jack beans, wherein the jack beans are reduced to a fine particle size and the fine particles so reduced constitute urease, the fine jack-bean particles thereafter irradiated for a period of time, the irradiated jack beans then recovered and employed as a source of urease enzyme, the improvement which comprises: irradiating the whole jack beans prior to any size reduction of the seeds of the jack beans, to provide a urease derived from the white seeds of the irradiated whole jack beans having an improved activity level.