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001-es BibID:	BIBFORM003923
Első szerző:	Damjanovich Sándor (biofizikus)
Cím:	The Role of the allosteric sites in the X-ray inactivation of phosphorylase b / S. Damjanovich, T. Sanner, A. Pihl
Dátum:	1967
Megjegyzések:	Crystalline rabbit muscle phosphorylase b was irradiated in dilute aqueous solution with X-rays. The enzyme was inactivated with a G-value of 0.09. Measurements of the K<sub>m</sub> values of the substrate, glucose-1-phosphate, and the allosteric activator, adenosine-5'-phosphate, demonstrated that these increased linearly with increasing radiation dose. The effect on the K<sub>m</sub> for the activator was 4 times greater than that on the K<sub>m</sub> for the substrate. The data indicate that the allosteric function is more sensitive to inactivation than the catalytic function. The enzyme SH-groups were destroyed by X-rays with a G-value of 1.8. Comparison with data on the inactivation of the enzyme by sulfhydryl blocking agents demonstrated that the X-ray destruction of sulfhydryl groups was sufficiently large to account for the X-ray inactivation of the enzyme. Blocking of two SH-groups with pCMB reduced the radiosensitivity of the enzyme by a factor of 2. Measurement of the K<sub>m</sub> values showed that the pCMB blocking protected preferentially the allosteric sites. The data indicate that the inactivation of phosphorylase b, both by sulfhydryl agents and by X-rays, involves largely an effect on the allosteric sites with loss of ability to bind the essential activator and consequent loss of ability to bind substrate.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban Allosteric regulation X-rays Irradiation Enzyme inhibitors Phosphorylase Allosteric enzymes
Megjelenés:	European Journal of Biochemistry. - 1 : 3 (1967), p. 347-352. -
További szerzők:	Sanner, Tore Pihl, Alexander
Internet cím:	elektronikus változat
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