Abstract |
The presence of a soluble, Mg2+- or Mn2+-dependent p-nitrophenylphosphatase activity in Ehrlich ascites tumor cell homogenates is reported. The crude homogenate was fractionated over Sephadex G-150 gel-filtration and DEAE-Sephacel anion-exchange columns, and two p-nitrophenylphosphatase activities were resolved. The most active fraction, Peak I, was characterized and found to be similar to phosphotyrosyl- protein phosphatases characterized elsewhere in that it has optimal activity at neutral pH; it is inhibited by phosphate, Zn2+, and vanadate; and it is not inhibited by levamisole. However, Peak I differs from phosphotyrosyl- protein phosphatases in that Mg2+ or Mn2+ is required for activity, fluoride is an inhibitor, and pyrophosphate is not inhibitory. Inhibition by the phosphorylated compounds phosphotyrosine, phosphoserine, phosphothreonine, ATP, CTP, GTP, ITP, NADP, fructose 6-phosphate, glucose 1-phosphate, galactose 1-phosphate, 2-phosphogluconic acid, and 6-phosphogluconic acid was also observed. Ehrlich ascites tumor cell p-nitrophenylphosphatase is shown to be sensitive to inactivation by trypsin, N-ethylmaleimide, or heat treatments.
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Authors | I Javeri, J Maxwell, O M Howard, S Yunker, S G O'Neal |
Journal | Archives of biochemistry and biophysics
(Arch Biochem Biophys)
Vol. 232
Issue 1
Pg. 214-22
(Jul 1984)
ISSN: 0003-9861 [Print] United States |
PMID | 6331318
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)
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Chemical References |
- Manganese
- Phosphoric Monoester Hydrolases
- 4-Nitrophenylphosphatase
- Trypsin
- Magnesium
- Ethylmaleimide
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Topics |
- 4-Nitrophenylphosphatase
(antagonists & inhibitors, metabolism)
- Animals
- Carcinoma, Ehrlich Tumor
(enzymology)
- Chromatography, Gel
- Ethylmaleimide
(pharmacology)
- Hot Temperature
- Hydrogen-Ion Concentration
- Magnesium
(metabolism)
- Male
- Manganese
(metabolism)
- Mice
- Mice, Inbred Strains
- Phosphoric Monoester Hydrolases
(metabolism)
- Phosphorylation
- Substrate Specificity
- Trypsin
(pharmacology)
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