Table 3.
Relative Molecular Species Production Rates for Proposed Variants of the Glutamate-Glutamine Cycle
| Molecule | Mechanism for Ammonium Transport | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Ammonium Diffusion | BCAA-BCKA Shuttle | Alanine-Lactate Shuttle | |||||||
| PN | A | Net | PN | A | Net | PN | A | Net | |
| xGlucose | 0 | 0 | 0 | 0 | −1/2 | −1/2 | −1/2 | 0 | −1/2 |
| dO2 | 0 | 0 | 0 | 0 | −3 | −3 | −2 1/2 | −1/2 | −3 |
| dCO2 | 0 | 0 | 0 | 0 | 3 | 3 | 3 | 0 | 3 |
| dH2O | −1 | 1 | 0 | 0 | 3 | 3 | 2 | 1 | 3 |
| xGlutamate | 1 | −1 | 0 | 1 | −1 | 0 | 1 | −1 | 0 |
| xGlutamine | −1 | 1 | 0 | −1 | 1 | 0 | −1 | 1 | 0 |
| dNH3 | 1 | −1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| xBCAA | 0 | 0 | 0 | 0 | 0 | 0 | 1 | −1 | 0 |
| xBCKA | 0 | 0 | 0 | 0 | 0 | 0 | −1 | 1 | 0 |
| xAlanine | 0 | 0 | 0 | 1 | −1 | 0 | 0 | 0 | |
| xLactate | 0 | 0 | 0 | −1 | 1 | 0 | 0 | 0 | 0 |
| xH+ | 1 | −1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Prefixes: extracellular (x) and diffusible (d).