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Endogenous phosphorylation and dephosphorylation of rat liver plasma membrane proteins, suggesting a 18 kDa phosphoprotein as a potential substrate for alkaline phosphatase.
- Source :
-
Biochimica et biophysica acta [Biochim Biophys Acta] 1992 Jan 09; Vol. 1118 (2), pp. 116-22. - Publication Year :
- 1992
-
Abstract
- Purified rat liver plasma membranes were incubated for 0-60 min with [gamma-32P]ATP and analysis of 32P-labeled proteins by means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography revealed the presence of two shifted kinetic phenomena. The use of 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H7), a potent inhibitor of protein kinases, allowed the identification of one as the endogenous protein phosphorylation. The other was shown to be the labeling of two phospho-intermediate forms of alkaline phosphatase (orthophosphoric monoester phosphohydrolase (alkaline optimum, EC 3.1.3.1.], which have apparent molecular masses of 151 and 135 kDa. Bromolevamisole, a potent inhibitor of the enzyme, stabilized these phospho-intermediates, and consequent on this inhibition the labelling of a 18 kDa phosphoprotein was augmented. So, when alkaline phosphatase was studied in its native plasma membrane environment, a specificity of this enzyme over the endogenous phosphoproteins was established.
- Subjects :
- 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine
Alkaline Phosphatase antagonists & inhibitors
Animals
Autoradiography
Cell Membrane enzymology
Electrophoresis, Polyacrylamide Gel
Isoquinolines pharmacology
Levamisole pharmacology
Liver cytology
Liver enzymology
Male
Phosphorylation
Piperazines pharmacology
Rats
Rats, Inbred Strains
Substrate Specificity
Alkaline Phosphatase metabolism
Liver metabolism
Membrane Proteins metabolism
Phosphoproteins metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0006-3002
- Volume :
- 1118
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Biochimica et biophysica acta
- Publication Type :
- Academic Journal
- Accession number :
- 1730026
- Full Text :
- https://doi.org/10.1016/0167-4838(92)90137-3