Equilibrium kinetics modal for the cGMP-stimulated phosphodiesterase of brain coated vesicles
Bol. Asoc. Méd. P. R
;
82(9): 407-11, Sept. 1990. tab
Artigo
em Inglês
| LILACS
| ID: lil-96165
ABSTRACT
An equilibrium kinetics model is proposed to described some of the enzymatic properties of the cyclic GMP-stimulated phosphodiesterase activity associated with brain clathrin coated vesicles. The model assumes the presence of pharmacologically distinct regultory and catalytic domains in the enzyme. The model contemplates that random fashion occupancy of the regulatory site by the substrate, cyclic GMP, induces a conformational change which leads to the generation of a actived catalytic state. Therefore, cyclic GMP is a positive allosteric modulator of the coated vesicle enzyme. Experimental data revealed that occupancy or activation of the regulatory site was not essential for catalysis to occur since hydrolysis occured after loss (200%) of the activation by cyclic GMP. This constitutes an example of non-essential substrate activation. Analysis of this PDE following activation by cGMP and after loss of the regulation, activation capacity of the enzyme allows the calculation of the various kinetic parameters inherent in the model
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Índice:
LILACS (Américas)
Assunto principal:
Membrana Celular
/
3',5'-GMP Cíclico Fosfodiesterases
/
Cérebro
/
Modelos Biológicos
Limite:
Animais
Idioma:
Inglês
Revista:
Bol. Asoc. Méd. P. R
Assunto da revista:
Medicina
Ano de publicação:
1990
Tipo de documento:
Artigo
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