抄録
The inactivation of unease by a heavy metal ion is intensified with the increasing pH of the medium, that is, a, less injurious heavy metal (Zn) is inhibitory only oil the alkaline side from about pH 6.0, but a more injurious metal (Call or Hg) is inhibitory both on the alkaline side and somewhat even on the acidic side.
This fact is very similar to the PH influence upon the combination of protein with a heavy metal observed by Kodama (1923). As regards the pH influence, the unknown inhibitors spontaneously contained in distilled water etc., reported in the preceding paper, are considered to be due to contamination with a trace of some heavy metal ions.
Free iodine is very injurious to urease compared with KI and the inactivation by KI increases on the acidic side inverse to those by a heavy metal ion.
