[Kinetics of dissociation of parvalbumin complexes with calcium and magnesium ions].
Dissociation kinetics of parvalbumin complexes with calcium and magnesium ions were studied by means of stopped-flow method employing intrinsic protein fluorescence registration. In the temperature range from 10 to 30 degrees C the kinetic curves of Ca2+ and Mg2+ dissociation are best fitted with a sum of two exponential terms, each term is ascribed to a dissociation process in one of two bindings sites of parvalbumin. Dissociation rate constants in this temperature range increase from 0.03 to 0.8 s-1 and from 0.18 to 5 s-1 for Ca2+, and from 0.9 to 4.5 s-1 and from 4 to 33 s-1 for Mg2+. Parvalbumin equilibrium binding constants of Ca2+ and Mg2+ were also measured in the same temperature range. It makes possible to estimate the rate constants of association of Ca2+ and Mg2+. In the case of Ca2+ the rate of association approaches the diffusion controlled limit.
Permiakov
E A
EA
Ostrovskiĭ
A V
AV
Kalinichenko
L P
LP
Deĭkus
G Iu
GIu
D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D005399:Fishes; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism*; D009124:Muscle Proteins / Q000378:metabolism*; D010320:Parvalbumins / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013696:Temperature; D013816:Thermodynamics
D009124:Muscle Proteins; D010320:Parvalbumins; D008274:Magnesium; D002118:Calcium
Kinetika dissotsiatsii kompleksov parval'bumina s ionami kal'tsiia i magniia.