TABLE 2.
Specific activities of Bm(Mdh-Act) and Bm(Mdh3-Act) and coupled specific activities of Bs(Hps-Phi) and Mg(Hps-Phi) in crude cell extracts of C. glutamicum strainsa
| Strain | Coupled HPS-PHI sp act (mU/mg) during: |
Mdh/Mdh3 sp act (mU/mg) during: |
||
|---|---|---|---|---|
| Exponential phase | Second growth phase | Exponential phase | Second growth phase | |
| Recombinant C. glutamicum strains | ||||
| Bm(mdh-act) Bs(hps-phi) | 73.3 ± 24.8 | 22.1 ± 7.9 | 0.4 ± 0.2 | 0.7 ± 0.5 |
| Bm(mdh-act) Mg(hps-phi) | 1.4 ± 1.6 | 1.0 ± 1.4 | ND | ND |
| Ptuf-Bm(mdh-act) Ptuf-Bs(hps-phi) | 53.1 ± 23.5 | 13.7 ± 1.3 | 3.3 ± 1.2 | 2.0 ± 1.5 |
| Recombinant C. glutamicum Δald ΔadhE strains | ||||
| Ptuf-Bm(mdh-act) Ptuf-Bs(hps-phi) | 45.3 ± 9.7 | 24.3 ± 15.3 | 5.5 ± 1.1 | 2.2 ± 1.8 |
| Ptuf-Bm(mdh3-act) Ptuf-Bs(hps-phi) | 36.3 ± 4.9 | 22.3 ± 12.1 | 6.0 ± 1.5 | 5.2 ± 1.9 |
| Ptuf-Bm(mdh-act) pEKEx2 | ND | ND | 5.5 ± 1.1 | 3.2 ± 2.3 |
a
Cells were cultivated in CGXII defined medium with 55 mM glucose and 120 mM methanol at 30°C with shaking at 120 rpm. Genes under the control of Ptac were induced with 1.5 mM IPTG at an OD600 of 1.0. Means and standard deviations were calculated from triplicates, and values were corrected for background activity. The background activity was determined in enzyme assays with the crude cell extracts of C. glutamicum(pVWEx2 pEKEx2) and C. glutamicum Δald ΔadhE(pVWEx2 pEKEx2). ND, not determined.