Endogenous phosphorylation and dephosphorylation of rat liver plasma membrane proteins, suggesting a 18 kDa phosphoprotein as a potential substrate for alkaline phosphatase.
Biochim Biophys Acta
; 1118(2): 116-22, 1992 Jan 09.
Article
em En
| MEDLINE
| ID: mdl-1730026
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.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fosfoproteínas
/
Fosfatase Alcalina
/
Fígado
/
Proteínas de Membrana
Limite:
Animals
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
1992
Tipo de documento:
Article
País de afiliação:
França