| Feature | Lactate | Acetyl-CoA | Oxaloacetate (OAA) | Alanine |
|---|---|---|---|---|
| Enzyme | Lactate Dehydrogenase (LDH) | Pyruvate Dehydrogenase Complex (PDC) | Pyruvate Carboxylase | Alanine Aminotransferase (ALT) |
| Location | Cytoplasm | Mitochondria | Mitochondria | Cytoplasm |
| Cofactor(s) | NADH (oxidized) | 5 Cofactors (Vits B1, B2, B3, B5, Lipoic Acid) | Biotin (B7), ATP | PLP (Vit B6) |
| Process | Reduction | Oxidative Decarboxylation (Irreversible) | Carboxylation | Transamination |
| Key State | Anaerobic / Hypoxia | Aerobic / Fed | Fasting / Gluconeogenesis | Fasting / Starvation |
| Primary Goal | Regenerate NAD⁺ for glycolysis (Cori Cycle) | Link glycolysis to TCA Cycle / FA synthesis | Replenish TCA (anaplerosis); Gluconeogenesis | Transport amino groups from muscle to liver (Glucose-Alanine Cycle) |