A soluble factor and GTP gamma S are required for Dictyostelium discoideum guanylate cyclase activity.
Biochim Biophys Acta
; 1135(1): 73-8, 1992 Apr 30.
Article
em En
| MEDLINE
| ID: mdl-1350467
ABSTRACT
Amoeba of Dictyostelium discoideum show a rapid, transient cGMP synthesis in response to chemotactic stimulation. Using Mg(2+)-GTP as a substrate, guanylate cyclase (E.C. 4.6.1.2.) activity is found exclusively in the particulate fraction of Dictyostelium cells. Here we show that the activity is dependent on the presence of the non-hydrolysable GTP-analogue GTP gamma S, which itself is only a poor substrate for the enzyme under the prevailing conditions. Evidence is presented that a transient exposure of the enzyme to GTP gamma S is sufficient to constitutively activate the enzyme. GTP gamma S-dependent activity is found to require a factor that can be separated from the enzyme by washing the particulate fraction with low salt buffer. Addition of the soluble cell fraction to these washed membranes restores enzyme activity.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Guanosina 5'-O-(3-Tiotrifosfato)
/
Dictyostelium
/
Guanilato Ciclase
Limite:
Animals
Idioma:
En
Ano de publicação:
1992
Tipo de documento:
Article