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. 2014 Dec 16;107(12):2993–3007. doi: 10.1016/j.bpj.2014.09.025

Table 1.

Best-fit examples of kinetic parameters for dihydrolipoamide dehydrogenase from various organisms

Parametera Rat liver enzyme
 Human liver enzyme
 E. coli enzyme
 Spinach enzyme
Single Kd set Sensitivityb Single Kd set Sensitivityb Single Kd set Multiple Kd set Sensitivityb Single Kd set Multiple Kd set Sensitivityb
k1 (min−1)c 4.05 × 104 — 1.26 × 107 — 1.11 × 109 — — 2.78 × 107 — —
k2 (min−1) 294 0.183 9.91 × 104 0.349 2.76 × 104 2.52 × 104 0.393 (0.727) 3.17 × 106 1.95 × 105 0.308 (1.04)
k3 (min−1) 2.56 × 104 0.103 1.06 × 104 0.176 1.32 × 104 9.76 × 104 0.0518 (0.138) 103 106 0.184 (0.135)
k4 (min−1) 107 0.127 8.64 × 105 0.186 1.25 × 106 2.38 × 106 0.0905 (0.111) 6.33 × 103 5.86 × 103 0.255 (0.294)
k5 (min−1)c 1.22 × 104 — 1.15 × 10−5 — 2.49 × 106 — — 3.42 × 105 — —
k6 (min−1) 5.56 × 103 0.538 10−3 8.62 × 10−4 70.2 581 0.218 (0.2) 103 1.47 × 103 0.670 (0.128)
k7 (min−1) 1.33 × 105 0.236 4.97 × 106 0.0212 1.21 × 105 1.52 × 106 0.430 (0.676) 2.60 × 104 3.85 × 103 0.520 (0.901)
k8 (min−1) 8.30 × 105 0.371 3.69 × 104 0.0213 107 8 × 106 0.389 (0.696) 6.43 × 106 5.0 × 104 0.487 (0.950)
pKh1 (thiolate) 6.98 0.044 7.32 0.349 7.5 7.34 0.399 (0.566) 5.67 4 0.297 (0.01)
pKh2 (base) 9 0.042 9 0.0281 8.56 8.85 0.193 (0.14) 9 8.9 0.030 (0.017)
KA1 (μM) 920 0.307 2.5 × 103 1.15 × 10−4 104 104 10−3 (1.2 × 10−17) 155 4.88 0.040 (6.4 × 10−18)
KB1 (μM) 1.74 × 103 0.388 1.1 0.177 498 498 0.439 (5.6 × 10−3) 2.70 2.55 0.361 (0.163)
KP1 (μM) 758 0.657 1.15 0.002 3.44 3.44 0.01 (5.6 × 10−18) 3.26 33.3 0.0393 (6.4 × 10−18)
KQ1 (μM) 1.24 × 103 0.487 70.5 0.18 520 520 0.370 (0.11) 3.55 1 0.338 (0.166)
KA2,3 (μM) — — — — — 55.6 9.9 × 10−4 — 5.05 × 103 0.0105
KB2,3 (μM) — — — — — 1.04 × 103 0.115 — 26.2 0.0701
KP2,3 (μM) — — — — — 1.67 0.254 — 19.6 0.0320
KQ2,3 (μM) — — — — — 429 0.604 — 1 0.0654
KA4 (μM) — — — — — 1.58 0.125 — 1 0.0610
KB4 (μM) — — — — — 230 0.683 — 26.6 0.380
KP4(μM) — — — — — 2.8 × 103 0.276 — 104 0.111
KQ4 (μM) — — — — — 1.63 0.680 — 104 0.0028
Keq (pH 7) 0.206d 0.734 0.0418 0.0696 0.153 0.103 0.168 (0.667) 0.0383 0.0446 0.302 (0.115)
a

Rate constants were constrained within the range 10−3 to 109 min−1 and equilibrium dissociation constants within the range 1 to 104μM. pKh1 and 2 were generally in the range between 4 and 9.

b

Sensitivities were calculated according to a previously described method (35); sensitivities in parentheses correspond to multiple Kd fits.

c

Parameter was solved for based on thermodynamic cycle constraints.

d

Rat liver enzyme data were collected at 37°C (22); thus, the equilibrium constant for these data was allowed to vary more from its known value at 25°C compared to the other data sets, which were collected at 25°C.