Studio Delle Sostanze di Origine Tumorale ad Azione Inibente Sulla Catalasi Epatica in Vivo

As an introduction to a series of papers on tumor substances inhibiting the activity of liver catalase, a critical review of the present situation of the general problem about the inhibition of this enzyme in tumor-bearing organisms is outlined. Data from researches carried out in order to determine the nature of the inhibitors are then exposed. « Toxohormone » was prepared from, human and experimental tumors and from ascitic fluids. It has been observed that, by the methods usually employed for such preparation, the 90–95 percent of the activity is lost.

Active, very heterogeneous fractions were obtained, by solvent extraction, from « toxohormone ». A globulin fraction from ascitic fluid proved very active; « toxohormone » was prepared also from this fraction but with a loss of 95 percent of the original activity. It is concluded that at least two categories of inhibitors exist, one of proteic nature, and one probably derived from the first, of low molecular weight. For the investigation of such substances, methods less damaging than those employed for « toxohormone » are necessary.