| AAV | adeno-associated virus |
| ALA | δ-aminolaevulinic acid |
| ALAD | δ-aminolaevulinic acid dehydratase |
| ALAS | δ-aminolaevulinic acid synthase |
| CYP | cytochrome P450-dependent oxidase |
| DPM | Dipyrromethane |
| E, E(holo) | holoenzyme |
| ES1–4 | Enzyme-substrate intermediates, with 1 to 4 substrate units |
| GABA | γ-aminobutyric acid |
| GATs | GABA transporters |
| HMB | 1-hydroxymethylbilane |
| HMBS | Hydroxymethylbilane synthase |
| PBG | Porphobilinogen |
| PEPT2 | peptide transporter 2 |
| PGC-1α | peroxisome proliferator-activated receptor γ coactivator 1α |
| ROS | reactive oxygen species |
| siRNA | small interference RNA |
| T m | half-denaturing temperature |
| UPS | ubiquitin-proteasome system |