TABLE 3.
Phosphofructokinase activity in extracts of Agrobacterium sp. strain ABR2 and Klebsiella sp. strain ABR11 grown on sulfoquinovose
| Source of enzyme | Kinase activitya (U/mg) towards
|
||
|---|---|---|---|
| Fructose 6-phosphate | Glucose 6-phosphate | Sulfoquinovose | |
| Extracts of ABR2 | 0.36 ± 0.02 | 0.51 ± 0.04 | 0.58 ± 0.05 |
| Extracts of ABR11 | 2.16 ± 0.82 | 2.68 ± 0.18 | 3.71 ± 0.06 |
| B. stearothermophilusb | 1.1 × 103 | NTc | NT |
a
Specific enzyme activities were measured by coupling ADP production to NADH oxidation in a coupled enzyme assay involving pyruvate kinase and lactate dehydrogenase (see text) and are expressed as units per milligram of protein ± standard deviation based on triplicate assays.
b
Purified phosphofructokinase from B. stearothermophilus (nominal 1.6 × 103 U/mg; Sigma-Aldrich) was used to validate the assay method.
c
NT, not tested; glucose 6-phosphate and sulfoquinovose are not substrates for the pure phosphofructokinase in the absence of phosphoglucose isomerase.