Table III.
Estimates of the anaplerotic inorganic carbon requirements
The calculations are based on data in Tables I and II, with morphometric data and assumptions of CO2 production rate in mitochondria in the light from Raven (2001), rate constants for uncatalyzed conversion of CO2 to HCO3- at 25°C, and 3.5‰ salinity as a function of pH calculated from Johnson (1982). Mitochondrial matrix pH = 7.8; cytosol pH = 7.4.
| Measurements
|
[NH4+] in the Growth Medium
|
||
|---|---|---|---|
| 0.1 mm | 1.0 mm | 10 mm | |
| HCO3- needed for N assimilation (mol cell-1 s-1) | 0.55×10-19 | 8.37×10-19 | 11.43×10-19 |
| Required rate of CO2→HCO3- for N assimilation if all HCO3- is made in mitochondria (mm s-1) | 0.27×10-1 | 3.32×10-1 | 2.95×10-1 |
| Required rate of CO2→HCO3- for N assimilation if all HCO3- is made in cytosol (mm s-1) | 0.17×10-2 | 2.20×10-2 | 2.03×10-2 |
| [CO2] in matrix if no CO2 in cytosol (mm) | 1.50×10-3 | 5.33×10-3 | 7.26×10-3 |
| Rate of uncatalyzed HCO3- production from matrix [CO2] (mm s-1) | 0.68×10-4 | 2.25×10-4 | 3.12×10-4 |
| [CO2] in the matrix needed if the uncatalyzed HCO3- production rate is to equal the required rate (mm) | 0.62 | 7.72 | 6.86 |
| [CO2] in the cytosol needed if the uncatalyzed HCO3- production rate is to equal the required rate (mm) | 0.05 | 0.56 | 0.51 |
| Rate of HCO3- production needed for N assimilation/computed rate of uncatalyzed HCO3- production in matrix | 10 | 98 | 64 |