Table 1.
Strain | Subunit V isozyme | YHb | NO production, pmol NO/g wet weight per min* | In vivo turnover rate, pmol NO × 10−1/min per pmol aa3† |
---|---|---|---|---|
JM43 | Va | + | 78 ± 32 | 0.07 ± 0.03 |
JM43ρ0 | Va | + | 00 ± 20 | - |
DR11 | Va | − | 240 ± 60 | 0.21 ± 0.05 |
DR10 | Va | − | 20 ± 10 | - |
GD5b | Va | + | 36 ± 32 | 0.04 ± 0.03 |
CT4F | Vb | + | 114 ± 32 | 0.30 ± 0.08 |
DW29 | Va | − | 168 ± 40 | 0.18 ± 0.04 |
DW27 | Vb | − | 336 ± 32 | 0.89 ± 0.08 |
*Cells (160 mg) were suspended in 2 ml of NO assay buffer and prebubbled for 5 min with N2 to create anoxic conditions. After 5 min of prebubbling NaNO2 was added to 1 mM, and NO production was measured with an NO polarographic electrode.
†Turnover rate was calculated by normalizing the rate of NO production to the cytochrome aa3 content of each strain, determined as described (31). Intracellular aa3 contents were 5.6 μM aa3/g wet weight for strains JM43 and DR11; 4.6 μM aa3/g wet weight for strains GD5b and DW29, and 1.9 μM aa3/g wet weight for strains CT4F and DW27. Strains JM43 ρ0 and DR10 lack detectable cytochromes aa3.