[Retarded conformational transitions in muscle glycogen phosphorylase b induced by specific ligands]. / Medlennye konformatsionnye perekhody v myshechnoi glikogenfosforilaze b, indutsiruemye spetsificheskimi ligandami.
Biokhimiia
; 59(4): 559-67, 1994 Apr.
Article
en Ru
| MEDLINE
| ID: mdl-8018778
The effect of specific ligands on the initial rate of muscle glycogen phosphorylase b digestion by trypsin has been studied. The kinetics of tryptic proteolysis were followed by measuring the decrease in phosphorylase b fluorescence intensity at 335 nm (excitation at 290 nm). The kinetic curves were linear at least in the region 0-400 s (0.02 M HEPES, pH 6.8; 37 degrees C). An allosteric activator (AMP) and allosteric inhibitors (flavins) protected the enzyme from tryptic digestion when trypsin was added to the enzyme preincubated with the ligand. Differences were found between the kinetic curves of trypsinolysis initiated by addition of the trypsin-ligand mixture to phosphorylase b an by addition of trypsin to the enzyme preincubated with the ligand for 10 min. It is concluded that the specific ligands under study (AMP, flavins, and the substrate--glucose 1-phosphate) induce relatively slow conformational changes in the phosphorylase b molecule with the half-conversion time of several minutes.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Fosforilasa b
/
Conformación Proteica
/
Músculos
Límite:
Animals
Idioma:
Ru
Revista:
Biokhimiia
Año:
1994
Tipo del documento:
Article
Pais de publicación:
Rusia