Table 1

ADP-kinetics of respiration in permeabilized fibres in mammalian R-solution

Temp

Creatine

n

V0

Vmax

ACR

KM ADP


10°C

-

5

2.28 ± 0.21

17.95 ± 2.59

7.90 ± 0.91

509 ± 57

+

5

2.15 ± 0.25

15.88 ± 2.59

7.38 ± 0.68

252 ± 48

15°C

-

5

3.39 ± 0.45

22.17 ± 3.46

6.62 ± 0.85

399 ± 34

+

5

3.30 ± 0.49

19.37 ± 3.69

5.82 ± 0.77

200 ± 17 *

20°C

-

5

5.48 ± 0.18

24.22 ± 1.97

4.42 ± 0.32

178 ± 32

+

5

5.21 ± 0.45

22.71 ± 3.78

4.26 ± 0.39

129 ± 30


Respiration was stimulated by increasing concentrations of ADP, and the kinetic parameters were calculated: V0 (nmol O2 min-1 mg dw-1) is the basal respiration rate before addition of ADP; Vmax (nmol O2 min-1 mg dw-1) is the maximal respiration rate at saturating ADP; ACR = Vmax/V0; KM ADP (μM) is the ADP-concentration at which V = Vmax/2. Vmax and KM ADP were calculated by a hyperbolic fit of the data. Experiments were performed at three different temperatures in the absence and presence of creatine. Number of experiments is given in column n. At each temperature, results in the absence and presence of creatine were compared by a paired Students t-test. * denotes P < 0.05 significantly different in the presence of creatine. The effect of creatine at 10°C was almost significant (P = 0.0533). Temperature-dependency was assessed by a one-way ANOVA in the absence and presence of creatine, respectively. Temperature had a significant effect on V0 (P < 0.001), ACR (P < 0.05) and KM ADP in the absence of creatine (P < 0.001).

Sokolova et al. BMC Cell Biology 2009 10:90   doi:10.1186/1471-2121-10-90

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