Steady-state kinetics of skeletal muscle myosin light chain kinase indicate a strong down regulation by products.
Standard
Steady-state kinetics of skeletal muscle myosin light chain kinase indicate a strong down regulation by products. / Geuss, U; Mayr, Georg W.; Heilmeyer, L M.
in: EUR J BIOCHEM, Jahrgang 153, Nr. 2, 2, 1985, S. 327-334.Publikationen: SCORING: Beitrag in Fachzeitschrift/Zeitung › SCORING: Zeitschriftenaufsatz › Forschung › Begutachtung
Harvard
APA
Vancouver
Bibtex
}
RIS
TY - JOUR
T1 - Steady-state kinetics of skeletal muscle myosin light chain kinase indicate a strong down regulation by products.
AU - Geuss, U
AU - Mayr, Georg W.
AU - Heilmeyer, L M
PY - 1985
Y1 - 1985
N2 - The kinetic behaviour of myosin light chain kinase isolated from skeletal muscle was studied under steady-state conditions using highly purified phosphorylatable light chains 2 (LC2). Forward reaction, product inhibition, and reverse reaction data indicate a sequential mechanism which can be interpreted best by a rapid-equilibrium random bi-bi reaction model. The forward reaction parameters are KATP = 150 microM, KLC2 = 5.3 microM, and Ki LC2 = 7.6 microM. The enzyme forms a dead-end complex with ADP and light chain 2; Kd, ADP of this complex is 50 microM. The forward reaction is also strongly inhibited by the phosphorylated light chain 2, Ki, LC2P is 1.5 microM. An equilibrium constant Keq of about 70 can be calculated from the kinetic parameters which agrees with the directly measured value of about 60. The role of the two inhibitory mechanisms in the regulation of the enzyme and of the high energy of the light chain phosphate bond as deducible from Keq are discussed.
AB - The kinetic behaviour of myosin light chain kinase isolated from skeletal muscle was studied under steady-state conditions using highly purified phosphorylatable light chains 2 (LC2). Forward reaction, product inhibition, and reverse reaction data indicate a sequential mechanism which can be interpreted best by a rapid-equilibrium random bi-bi reaction model. The forward reaction parameters are KATP = 150 microM, KLC2 = 5.3 microM, and Ki LC2 = 7.6 microM. The enzyme forms a dead-end complex with ADP and light chain 2; Kd, ADP of this complex is 50 microM. The forward reaction is also strongly inhibited by the phosphorylated light chain 2, Ki, LC2P is 1.5 microM. An equilibrium constant Keq of about 70 can be calculated from the kinetic parameters which agrees with the directly measured value of about 60. The role of the two inhibitory mechanisms in the regulation of the enzyme and of the high energy of the light chain phosphate bond as deducible from Keq are discussed.
M3 - SCORING: Zeitschriftenaufsatz
VL - 153
SP - 327
EP - 334
IS - 2
M1 - 2
ER -
