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Table 2 Kinetic constants and Tm values for the wild-type and mutant 17β-HSDcl

From: Dimerization and enzymatic activity of fungal 17β-hydroxysteroid dehydrogenase from the short-chain dehydrogenase/reductase superfamily

 

*K d NADP+(μM)

K M NADPH(μM)

K M NADP+(μM)

k cat NADPH(s-1)

k cat NADP+(s-1)

k cat /KM, NADPH(s-1M-1)

k cat /KM, NADP+(s-1M-1)

Tm (°C)

Wild type

0.2

6.5

0.06

3.8

0.65

5.8 × 105

1.1 × 107

44

His111Ala

5.8

50.6

4.6

2.4

0.9

4.7 × 104

1.9 × 105

37

His111Leu

19.9

N.A.

N.A.

N.A.

N.A.

N.A.

N.A.

48

Arg129Asp

12.8

N.A.

N.A.

N.A.

N.A.

N.A.

N.A.

50

  1. Kinetic constants for the reduction and oxidation of the substrates 4-estrene-3,17-dione and 4-estrene-17β-ol-3-one (100 μM) (Keq = 2.46 ± 0.11 [38]) that were catalyzed by the wild-type and mutant 17β-HSDcl in the presence of the coenzymes NADPH and NADP+ (100 μM), at pH 8 and 25°C. The temperature midpoints (Tm) are also given. (* determined by fluorescence titrations; N.A.: no activity detected)
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BMC Biochemistry

ISSN: 1471-2091

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