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Adenylate activation of wood frog skeletal muscle AMPD from control versus frozen frogs |
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| Control |
Frozen |
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| Free AMPD |
Bound AMPD |
Free AMPD |
Bound AMPD |
|
|
|
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| Ka Mg·ATP, mM |
1.90 ± 0.03 |
NE |
0.63 ± 0.04 a |
NE |
| Mg·ATP fold-activation |
1.53 ± 0.09 |
NE |
2.69 ± 0.20 a |
NE |
| Ka Mg·ADP, mM |
1.12 ± 0.15 b |
3.75 ± 0.37 |
0.54 ± 0.02 ab |
1.14 ± 0.10 a |
| Mg·ADP fold-activation |
2.17 ± 0.29 |
1.25 ± 0.21 |
5.01 ± 0.69 a |
3.42 ± 0.24 a |
|
Data are means ± SEM, for determinations on Sephadex G50-filtered muscle extracts from n = 4 individual frogs. Significantly different from a the corresponding value in control frogs, b the corresponding value for bound AMPD in control frogs, by the Student's t-test, P < 0.05. NE, no effect. Ka is the activator concentration that produces half-maximal activation; values were determined at 0.5 mM AMP. Ka and fold activation values were calculated using a nonlinear least-squares regression kinetics program [39]. | ||||
Dieni and Storey BMC Biochemistry 2008 9:12 doi:10.1186/1471-2091-9-12 |
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