SULT Isoform: Substrate Specificity | kcat | Km | kcat/Km | Relative Activity |
---|---|---|---|---|
pmol min−1 μg−1 | μM | μl min−1 μg−1 | ||
1A1∗2: PNP thermostable I | 10.6 | 300 | 0.035 | 1 |
1E: estrone | 20 | 1000 | 0.020 | 0.6 |
2A1: DHEA | 3.8 | 500 | 0.0076 | 0.2 |
1A2∗1: PNP thermostable II | <0.05 | |||
1A3: dopamine thermolabile | <0.05 |
Various concentrations of genistein and daidzein were incubated with recombinant microsomal SULTs as described in the text, and the kinetics of product formation were determined using LC-UV. No product formation was observed with daidzein. The detection limit was approximately 0.05 pmol min−1 μg−1 for genistein and daidzein. Measurement of relative activity is based onkcat/Km ratios.