Study of the inhibition of neutral phosphatase from Pseudomonadaceae by derivatives of its substrates
Krupianko, V.I.; Severin, A.I.; Stepnaia, O.A.; Kozlovskiĭ, A.G.; Kulaev, I.S.
Biokhimiia 54(10): 1658-1665
1989
ISSN/ISBN: 0320-9725 PMID: 2557930 Document Number: 337332
The inhibition of neutral phosphatase isolated from the bacteria of the Pseudomonadaceae family by various fragments of the enzyme-hydrolyzed R-O-PO3H2 substrates, inorganic orthophosphate (KH2PO4) and its analogs as well as by adenine, adenosine, alcohols, sugars and amino acids, was studied. It was demonstrated that among other compounds tested only the orthophosphoric acid anions (H2PO4-) exhibit the properties of strong associative inhibitors (K1Vi = 4.35.10(-6)M of the enzyme. The pH dependence of the Michaelis constant [pKm0 = f(pH)] and the inhibition constant for phosphatase by potassium orthophosphate [pK1Vi(KH2PO4) = f(pH)] was studied. The presence in the enzyme active center of a carboxylic (pK = 4.3 +/- 0.1) (presumably, glutamine) and an imidazole (pK = 7.15 +/- 0.1) amino acid residues was postulated. The data obtained were compared to those for neutral, alkaline and acid phosphatases.