TABLE 2.
Fractionation of the hydrogenase activity of P. grassii cellsa
| Fraction | Value at pH 8 for:
|
Value at pH 6 for:
|
||
|---|---|---|---|---|
| Evolution | Uptake | Evolution | Uptake | |
| Cell homogenate | 33 ± 6 | 325 ± 17 | 230 ± 21 | 464 ± 32 |
| 500 × g ppt (large particles) | 67 ± 15 | 113 ± 11 | 93 ± 13 | 141 ± 23 |
| 2,000 × g ppt (hydrogenosomes) | 4,268 ± 126 | 2,778 ± 119 | 28 ± 7 | 223 ± 41 |
| 10,000 × g ppt (bacteria) | 71 ± 19 | 11,852 ± 337 | 573 ± 46 | 14,183 ± 632 |
| 10,000 × g supernatant (soluble material) | 18 ± 10 | 51 ± 13 | ND | 35 ± 15 |
a
The mean hydrogenase activity (± the standard deviation) measured at either pH 8 or pH 6 is expressed as nanomoles of H2 per minute per milligram. ND, not detected. The hydrogenosome-rich fraction (2,000 × g ppt) showed that only 10.9% of the observed particles stained with DAPI, whereas 79.5% of the particles in the endosymbiotic bacterial fraction (10,000 × g ppt) stained with DAPI.