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Kinetics of ATP Release and Pi Binding During the ATPase Cycle of Lethocerus Flight Muscle Fibres, Using Phosphate-water Oxygen Exchange

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Specialties Cell Biology
Physiology
Date 1991 Jun 1
PMID 1831462
Citations 1
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Abstract

Rate constants have been obtained using oxygen isotope exchange techniques for steps controlling ATP release and Pi binding in the ATPase cycle of insect flight muscle fibres from the giant waterbug Lethecerus. The new exchange data for Pi binding and ATP release are compatible with a model developed previously in which only the rate constants controlling Pi and ATP release change during fibre activation. Phosphate-water oxygen exchange occurs into ATP remaining after partial hydrolysis by chemically skinned fibres in (18O) water. For fully activated fibres, the results are compatible with a single set of rate constants controlling this exchange and give a rate constant for ATP release of 1 s-1 (21 degrees C, pH 7.0 I = 120 mM). Oxygen exchange also occurs between (18O4)Pi in the medium and water during ATP hydrolysis. There is a strong correlation between the measured rate constant of exchange and the value of keat for the ATPase activity at different levels of activation. For fibres fully activated by oscillation or strain, the rate constant for Pi binding to an actomyosin. ADP state is greater than 960 M-1 s-1.

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References
1.
Shoshan V, Maclennan D . Quercetin interaction with the (Ca2+ + Mg2+)-ATPase of sarcoplasmic reticulum. J Biol Chem. 1981; 256(2):887-92. View

2.
Ferenczi M . Phosphate burst in permeable muscle fibers of the rabbit. Biophys J. 1986; 50(3):471-7. PMC: 1329723. DOI: 10.1016/S0006-3495(86)83484-1. View

3.
Chaplain R, Tregear R . The mass of myosin per cross-bridge in insect fibrillar flight muscle. J Mol Biol. 1966; 21(2):275-80. DOI: 10.1016/0022-2836(66)90098-2. View

4.
Bowater R, Webb M, Ferenczi M . Measurement of the reversibility of ATP binding to myosin in calcium-activated skinned fibers from rabbit skeletal muscle. Oxygen exchange between water and ATP released to the solution. J Biol Chem. 1989; 264(13):7193-201. View

5.
Webb M, McDonald G, Trentham D . Kinetics of oxygen-18 exchange between inorganic phosphate and water catalyzed by myosin subfragment 1, using the 18O shift in 31P NMR. J Biol Chem. 1978; 253(9):2908-11. View