title: [Inhibition of alkaline phosphatase I of Pichia guilliermondii yeast in vitro and in vivo].
abstract: The rate of p-nitrophenyl phosphate and flavin mononucleotide (FMN) hydrolysis by the partially purified preparation of alkaline phosphatase I of Pichia guilliermondii flavinogenic yeast was studied as affected by different substrates and inorganic ions. Their Km was established to be 2.0 X 10(-4) m and 2.5 X 10(-4) M, respectively. Dephosphorylation of p-nitrophenylphosphate and FMN was inhibited competitively by beta-glycerophosphate (Ki = 3.1 X 10(-3) M, respectively). The presence of inorganic phosphate ions in the reaction mixture decreases or removes inhibition of these compounds hydrolysis by other substrates of alkaline phosphatase I. The activity of alkaline phosphatase I increases in the presence of Mg2+ and was strongly inhibited in the presence of Be2+, Cu2+, Zn2+, Cd2+ and inorganic phosphate, the mixture of Be2+ and F- being the most effective. This mixture inhibited the phosphatase activity of the partially purified preparation of alkaline phosphatase I of the cell-free extract as well as of intact cells in both the alkaline and acid zones of pH (8.6 and 5.5, respectively). Incubation of the washed iron-deficient P. guilliermondii cells in the presence of Be2+ and F- did not result in accumulation of FMN in the yeast culture. A possible role of nonspecific phosphomonoesterases in hydrolysis of FMN in vivo is discussed.
mesh_terms: D009597:4-Nitrophenylphosphatase / Q000037:antagonists & inhibitors; D000469:Alkaline Phosphatase / Q000037:antagonists & inhibitors*; D001203:Ascomycota / Q000201:enzymology*; D001608:Beryllium / Q000494:pharmacology; D002413:Cations, Divalent; D005486:Flavin Mononucleotide / Q000378:metabolism; D005459:Fluorides / Q000494:pharmacology; D005994:Glycerophosphates / Q000494:pharmacology; D007700:Kinetics; D010710:Phosphates / Q000494:pharmacology; D010843:Pichia / Q000187:drug effects / Q000201:enzymology*
chemical_list: D002413:Cations, Divalent; D005994:Glycerophosphates; D010710:Phosphates; D005486:Flavin Mononucleotide; D000469:Alkaline Phosphatase; D009597:4-Nitrophenylphosphatase; D001608:Beryllium; D005459:Fluorides
vernacular_title: Ob ingibirovanii shchelochoni fosfatazy I drozhzhei Pichia guilliermondii in vitro i in vivo.