University of Michigan, Ann Arbor, MI 48109 USA
| 1.01. | Receptors (68 superfamilies) | |
| 1.02. | Ligands (48 superfamilies) | |
| 1.03. | Structural/adhesion proteins (58 superfamilies) | |
| 1.04. | Protein biogenesis and transport (41 superfamilies) | |
| 1.05. | Membrane remodeling (13 superfamilies) | |
| 1.06. | Transport of nonproteins (25 superfamilies) | |
| 1.07. | Gene expression (8 superfamilies) | |
| 1.08. | Protein degradation (5 superfamilies) | |
| 1.09. | Enzymes, oxidoreductases (EC 1.) (38 superfamilies) | |
| 1.10. | Enzymes, transferases (EC 2.) (29 superfamilies) | |
| 1.11. | Enzymes, hydrolases (EC 3.) (34 superfamilies) | |
| 1.12. | Enzymes, lyases (EC 4.) (4 superfamilies) | |
| 1.13. | Enzymes, isomerases (EC 5.) (4 superfamilies) | |
| 1.14. | Enzymes, ligases (EC 6.) (2 superfamilies) | |
| 1.15. | Proteins of unknown function (70 superfamilies) |