Comparison of the activities of a multiple inositol polyphosphate phosphatase obtained from several sources: a search for heterogeneity in this enzyme
- 15 January 1995
- journal article
- research article
- Published by Portland Press Ltd. in Biochemical Journal
- Vol. 305 (2), 491-498
- https://doi.org/10.1042/bj3050491
Abstract
A multiple inositol polyphosphate phosphatase (formerly known as inositol 1,3,4,5-tetrakisphosphate 3-phosphatase) was purified approx. 22,000-fold from rat liver. The final preparation migrated on SDS/PAGE as a doublet with a mean apparent molecular mass of 47 kDa. Upon size-exclusion chromatography, the enzyme was eluted with an apparent molecular mass of 36 kDa. This enzyme was approximately evenly distributed between the ‘rough’ and ‘smooth’ subfractions of endoplasmic reticulum. There was a 20-fold range of specific activities of this phosphatase in CHAPS-solubilized particulate fractions prepared from the following rat tissues: liver, heart, kidney, testis and brain. However, each of these extracts contained different amounts of endogenous inhibitors of enzyme activity. After removal of these inhibitors by MonoQ anion-exchange chromatography, there was only a 2.5-fold range of specific activities; kidney contained the most and brain contained the least. We prepared and characterized polyclonal antiserum to the hepatic phosphatase, which immunoprecipitated 85-100% of both particulate and soluble phosphatase activities. The antiserum also immunoprecipitated, with equivalent efficacy, CHAPS-solubilized phosphatase activities from heart, kidney, testis, brain and erythrocytes (all prepared from rat). Our data strengthen the case that the function of the mammalian phosphatase is unrelated to the metabolism of Ca(2+)-mobilizing cellular signals. The CHAPS-solubilized phosphatase from turkey erythrocytes was not immunoprecipitated by the polyclonal antiserum, and is therefore an isoform that is structurally distinct, and possibly functionally unique.Keywords
This publication has 26 references indexed in Scilit:
- Turkey erythrocytes possess a membrane-associated inositol 1,4,5-trisphosphate 3-kinase that is activated by Ca2+ in the presence of calmodulinBiochemical Journal, 1987
- Evidence for a lack of inositol - (1,4,5)trisphosphate kinase activity in norepinephrine-perfused rat heartsBiochemical and Biophysical Research Communications, 1987
- Semi-intact cells permeable to macromolecules: Use in reconstitution of protein transport from the endoplasmic reticulum to the Golgi complexCell, 1987
- The inositol trisphosphate phosphomonoesterase of the human erythrocyte membraneBiochemical Journal, 1982
- Metal ion-promoted binding of proteins to immobilized triazine dye affinity adsorbentsBiochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, 1982
- A Rapid and Sensitive Method for the Quantitation of Microgram Quantities of Protein Utilizing the Principle of Protein-Dye BindingAnalytical Biochemistry, 1976
- [2] Subcellular fractionation of rat liverMethods in Enzymology, 1974
- A comparative study of the molecular structures of the plasma membranes and the smooth and the rough endoplasmic-reticulum membranes from rat liverBiochemical Journal, 1972
- Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4Nature, 1970
- Recent developments in the measurement of nucleic acids in biological materials. A supplementary reviewThe Analyst, 1966