[Kinetics of dissociation of alpha-lactalbumin complexes with Ca2+ and Mg2+ ions]. / Kinetika dissotsiatsii kompleksov alpha-laktal'bumina s ionami Ca2+ i Mg2+.
Biofizika
; 33(3): 413-6, 1988.
Article
en Ru
| MEDLINE
| ID: mdl-3167106
Kinetics of dissociation of the complexes of bovine alpha-lactalbumin with Ca2+ and Mg2+ ions induced by mixing of the Ca2+- or Mg2+-loaded protein with the chelator of divalent cations EDTA has been studied by means of intrinsic fluorescence stopped flow method. Within the temperature region from 10 to approximately 37 degrees C the fluorescence kinetics curves for the Ca2+ removal are well fitted by one exponent with the rate constant ranging from 6.10(-3) to 1 s-1. Taking into account rather low rate of the fluorescence changes, one can assume that the limiting stage in this case is the dissociation of the single bound Ca2+ ion from the protein but not a conformational change which occurs after the Ca2+ dissociation. At temperatures above 37 degrees C the kinetics curves are best fitted by two exponents. The second exponent seems to be due to the denaturation of the apo-form of alpha-lactalbumin which takes place at these temperatures. The values of the dissociation rate constants of Mg2+ practically coincide with the values for Ca2+.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Calcio
/
Lactalbúmina
/
Magnesio
Límite:
Animals
Idioma:
Ru
Revista:
Biofizika
Año:
1988
Tipo del documento:
Article
Pais de publicación:
Rusia