Studies on protein methyltransferase in human cerebrospinal fluid.
J Mol Neurosci
; 1(3): 151-7, 1989.
Article
em En
| MEDLINE
| ID: mdl-2484441
Protein methyltransferases, rich in most mammalian brains, were studied in human cerebrospinal fluid (CSF). Among several well-characterized groups of methyltransferases, protein methylase I (S-adenosylmethionine:protein-arginine N-methyltransferase, EC 2.1.1.23) was found in significant amounts in human CSF samples. Both myelin basic protein (MBP) -specific and histone-specific protein methylase I activities were observed, the latter being generally higher in most CSF. S-Adenosyl-L-homocysteine, a potent product inhibitor for the methyltransferase, inhibited approximately 90% of MBP-specific protein methylase I activity at a concentration of 1 mM. The optimum pH of the MBP-specific protein methylase I was found to be around 7.2. Identity of exogenously added MBP as the methylated substrate for CSF enzyme was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. An amino acid analysis of the [methyl-3H]protein hydrolysate showed two major radioactive peaks cochromatographing with monomethyl- and dimethyl (symmetric)-arginine. Human CSF contained relatively high endogenous protein methylase I activity (activity measured without added substrate protein): The endogenous substrate can be immunoprecipitated by antibody raised against calf brain MBP. Finally, CSF from several neurological patients were analyzed for protein methylase I, and the results are presented.
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Base de dados:
MEDLINE
Assunto principal:
Proteínas Metiltransferases
Limite:
Humans
Idioma:
En
Ano de publicação:
1989
Tipo de documento:
Article