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Abstract

An apparatus adapted for urease determination using 14C-urea was tested with jack bean urease (Toyobo Co., Ltd.), and found to be time-saving, accurate and easy to operate, although it was preferable to use it in samples free from other sources of urea. The use of the apparatus enabled to demonstrate the existence of urease in the hemolymph of pupae reared on mulberry leaves, but not in those reared on an artificial diet. Also, it was found that the failure to detect urease in the hemolymph of the latter group was not caused by the presence of an inhibitor, but by the absence of the enzyme itself in these materials.