Unusual Course of the p-Nitrophenyl Phosphate Esters Cleavage by 3-Hydroxyiminoalkylpyridinium Salts in Micellar Solutions

1998 ◽  
Vol 27 (7) ◽  
pp. 649-650 ◽  
Author(s):  
Hana Kotoucová ◽  
Jirí Mazac ◽  
Radek Cibulka ◽  
František Hampl ◽  
František Liška
Keyword(s):  
Phosphate Esters ◽  
Micellar Solutions ◽  
Nitrophenyl Phosphate

scholarly journals Subcellular localization and tissue distribution of sialic acid-forming enzymes. N-acetylneuraminate-9-phosphate synthase and N-acetylneuraminate 9-phosphatase

1984 ◽  
Vol 223 (2) ◽  
pp. 323-328 ◽  
Author(s):  
J Van Rinsum ◽  
W Van Dijk ◽  
G J Hooghwinkel ◽  
W Ferwerda
Keyword(s):  
Subcellular Localization ◽  
Biosynthetic Pathway ◽  
Cytosolic Fraction ◽  
Phosphate Esters ◽  
Rat Tissues ◽  
Acetylneuraminic Acid ◽  
Nitrophenyl Phosphate ◽  
Sucrose Medium ◽  
Hydrolysis Of ◽  
Phosphate Synthase

The activities of N-acetylneuraminate 9-phosphate synthase and N-acetylneuraminate 9-phosphatase, the two enzymes involved in the final steps of the biosynthetic pathway of N-acetylneuraminic acid, were measured with the substrates N-acetyl[14C]mannosamine 6-phosphate and N-acetyl[14C]neuraminic acid 9-phosphate respectively. Subcellular localization studies in rat liver indicated that both enzymes are localized in the cytosolic fraction after homogenization in sucrose medium. To test the possibility of misinterpretation due to the hydrolysis of N-acetylneuraminic acid 9-phosphate by non-specific phosphatases, the hydrolysis of various phosphate esters by the cytosolic fraction was tested. Only p-nitrophenyl phosphate was hydrolysed; however, competition studies with N-acetylneuraminic acid 9-phosphate and p-nitrophenyl phosphate indicated that two different enzymes were involved and that no competition existed between the two substrates. In various other rat tissues N-acetylneuraminate-9-phosphate synthase and N-acetylneuraminate 9-phosphatase activities were detected, suggesting that N-acetylmannosamine 6-phosphate is a general precursor for N-acetylneuraminic acid biosynthesis in all the tissues studied.

Acid phosphatase activity demonstrated by intact Angiostrongylus cantonensis with special reference to its function

Parasitology ◽  
1979 ◽  
Vol 79 (3) ◽  
pp. 417-423 ◽  
Author(s):  
Jun Maki ◽  
Toshio Yanagisawa
Keyword(s):  
Acid Phosphatase ◽  
External Medium ◽  
Reciprocal Inhibition ◽  
Angiostrongylus Cantonensis ◽  
Phosphate Esters ◽  
Glucose Phosphate ◽  
Nitrophenyl Phosphate ◽  
Inhibition Studies ◽  
Hydrolysis Of

SUMMARYIntact Angiostrongylus cantonensis is able to hydrolyse glucose-phosphate esters, mononucleotides and p-nitrophenyl phosphate as well as β-glycerophosphate in vitro. Reciprocal inhibition studies suggest that the hydrolysis of such substrates is due to a non-specific phosphomonoesterase. Molybdate ions, which exert no effect on either the uptake of glucose or the production of lactate, inhibit the hydrolysis of glucose-1- phosphate in the external medium and simultaneously lower the production of lactate by the intact worms in vitro.

scholarly journals The presence of a Zn2+-dependent acid p-nitrophenyl phosphatase in bovine liver. Isolation and some properties

1986 ◽  
Vol 235 (1) ◽  
pp. 265-268 ◽  
Author(s):  
F Panara
Keyword(s):  
Catalytic Activity ◽  
Bovine Liver ◽  
Phosphate Esters ◽  
Acid Phosphatases ◽  
Bivalent Cations ◽  
Apparent Homogeneity ◽  
Nitrophenyl Phosphate ◽  
Mammalian Tissues ◽  
Optimum Ph ◽  
The Common

The presence of a Zn2+-dependent acid p-nitrophenyl phosphatase (EC 3.1.3.2) in bovine liver was described. The enzyme was purified to apparent homogeneity and migrates as a single band during electrophoresis on polyacrylamide gel. The enzyme requires Zn2+ ions for catalytic activity, other bivalent cations have little or no effect. The enzyme, of Mr 118,000, optimum pH 6-6.2 and pI 7.4-7.5, was inhibited by EDTA, tartrate, adenine and ATP, but not by fluoride. The common phosphate esters are poor substrates for the enzyme, which hydrolyses preferentially p-nitrophenyl phosphate and o-carboxyphenyl phosphate. The Zn2+-dependent acid p-nitrophenyl phosphatase of bovine liver was different from the high-Mr acid phosphatases previously detected in mammalian tissues.

Substituent Effects on the Thermal Decomposition of Phosphate Esters on Ferrous Surfaces

2019 ◽  
Author(s):  
James Ewen ◽  
Carlos Ayestaran Latorre ◽  
Arash Khajeh ◽  
Joshua Moore ◽  
Joseph Remias ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Film Formation ◽  
Substituent Effects ◽  
Vapour Phase ◽  
Industrial Applications ◽  
Phosphate Esters ◽  
Antiwear Additives ◽  
Formation Mechanisms ◽  
Phosphate Ester ◽  
Wide Range

<p>Phosphate esters have a wide range of industrial applications, for example in tribology where they are used as vapour phase lubricants and antiwear additives. To rationally design phosphate esters with improved tribological performance, an atomic-level understanding of their film formation mechanisms is required. One important aspect is the thermal decomposition of phosphate esters on steel surfaces, since this initiates film formation. In this study, ReaxFF molecular dynamics simulations are used to study the thermal decomposition of phosphate esters with different substituents on several ferrous surfaces. On Fe<sub>3</sub>O<sub>4</sub>(001) and α-Fe(110), chemisorption interactions between the phosphate esters and the surfaces occur even at room temperature, and the number of molecule-surface bonds increases as the temperature is increased from 300 to 1000 K. Conversely, on hydroxylated, amorphous Fe<sub>3</sub>O<sub>4</sub>, most of the molecules are physisorbed, even at high temperature. Thermal decomposition rates were much higher on Fe<sub>3</sub>O<sub>4</sub>(001) and particularly α-Fe(110) compared to hydroxylated, amorphous Fe<sub>3</sub>O<sub>4</sub>. This suggests that water passivates ferrous surfaces and inhibits phosphate ester chemisorption, decomposition, and ultimately film formation. On Fe<sub>3</sub>O<sub>4</sub>(001), thermal decomposition proceeds mainly through C-O cleavage (to form surface alkyl and aryl groups) and C-H cleavage (to form surface hydroxyls). The onset temperature for C-O cleavage on Fe<sub>3</sub>O<sub>4</sub>(001) increases in the order: tertiary alkyl < secondary alkyl < primary linear alkyl ≈ primary branched alkyl < aryl. This order is in agreement with experimental observations for the thermal stability of antiwear additives with similar substituents. The results highlight surface and substituent effects on the thermal decomposition of phosphate esters which should be helpful for the design of new molecules with improved performance.</p>

An Indication that Chloride Affects the Phosphate Esters in Tubers of the White Potato 1

1959 ◽  
Vol 51 (12) ◽  
pp. 750-751 ◽  
Author(s):  
H. W. Gausman ◽  
G. R. Cooper ◽  
R. A. Struchtemeyer
Keyword(s):  
Phosphate Esters ◽  
White Potato
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