| CTZ | coelenterazine |
| CTM | coelenteramide, decarboxylated derivative of CTZ |
| Luc | luciferase |
| PhP | Ca2+-regulated photoprotein |
| apoPhP | polypeptide part of PhP |
| CBP | Ca2+-dependent coelenterazine-binding protein |
| apoCBP | polypeptide part of CBP |
| GFP | green fluorescent protein |
| EF-hand | The Ca2+-binding sites formed by helix-loop-helix motifs |