抄録
1. The stoichiometric studies on the reaction of diphenethynyl mercury and gluta-thione were carried out spectrophotometrical-ly. It was found that 1 to 2 moles of the mercurial and glutathione, respectively, gave I mole of diglutathionyl mercury and 2 moles of phenylacetylene. These final prodocts were always found to be produced, independent of the initial molar ratios of these two reac-tants.
2. Kinetical studies performed on this reaction system revealed that a first-order reaction was rate-limiting process on the mole-cule of diphenethynyl mercury and that more complicated reaction process occurring on glutathione molecule. Possible reaction schemes on this reaction system are presented.
3. The spectrophotometric method was also applied to the study on the reactivity of diphenethynyl mercury with urease protein. It was concluded that diphenethynyl mercury reacted easily with “reactive” sulfhydryl groups of urease protein, whereas it reacted slowly with “sluggish” ones. This view was further supported by the fact that diphenet hynyl mercury exhibited only a partial inhibition on the ureolytic activity of urease; the cite of enzymatic activity of this enzyme has been known to be involved in the reac-tivity of the “sluggish” sulfhydryl groups in the protein molecule.
The author wishes to express his deep gratitude to Prof. T. Yanagita of Chiba University and Prof. A. T akamiya of University of Tokyo for their kind guidance and encouragement throughout this work. Thanks are due to Mr. M. Matsui, Director, and Dr. Y. Miura of this Laboratory for their kind encouragement, and to Dr. S. 0saki of Tokyo Institute of Technology for his technical guidance in ultracentrifugation.
The author is indebted to Messrs. T. Onoe, O. Amakasu, and H. Higuchi, and to Misses C. Furukawa and H. Ohtsuka of this Labora-tory, for elemental analyses and infrared spectral measurements.
