Table 2.
Methyl-THMPT:HSCoM methyltransferase activity in the soluble and membrane fractions of CO- or methanol-grown Methanosarcina acetivorans
| Fraction | Total protein (mg) |
Total activitya (U) |
Sp act (U/mg) |
Total activity (%) |
||||
|---|---|---|---|---|---|---|---|---|
| CH3OH | CO | CH3OH | CO | CH3OH | CO | CH3OH | CO | |
| Extract | 50.0 | 50.0 | 6.15 ± 0.45 | 10.9 ± 1.1 | 0.12 ± 0.02 | 0.22 ± 0.03 | 100 | 100 |
| Soluble | 37.5 | 41.4 | 0.79 ± 0.15 | 7.5 ± 0.8 | 0.02 ± 0.005 | 0.18 ± 0.02 | 12.7 | 69.0 |
| Membrane | 4.5 | 3.5 | 4.77 ± 0.43 | 3.2 ± 0.2 | 1.06 ± 0.06 | 0.92 ± 0.08 | 77.5 | 29.0 |
a
The 100-μl assay was performed at 37°C in 50 mM MOPS-KOH (pH 7.0) containing 100 μg CmtA reconstituted with aquocobalamin, 1 mM Ti(III)-citrate, 5 mM methyl viologen, 10 mM MgCl2, 10 mM ATP, 5 mM methyl donor, 5 mM HS-CoM, and 5 mM potassium 2-bromoethanesulfonate. Unit (U) indicates μmol CH3-S-CoM/min.