| Functional categories | Code | Description | |
|---|---|---|---|
| Information storage and processing | |||
| J | Translation, ribosomal structure and biogenesis | ||
| A | RNA processing and modification | ||
| K | Transcription | ||
| L | Replication, recombination and repair | ||
| B | Chromatin structure and dynamics | ||
| Cellular processes and signaling | |||
| D | Cell cycle control, cell division, chromosome partitioning | ||
| Y | Nuclear structure | ||
| V | Defense mechanisms | ||
| T | Signal transduction mechanisms | ||
| M | Cell wall/membrane/envelope biogenesis | ||
| N | Cell motility | ||
| Z | Cytoskeleton | ||
| W | Extracellular structures | ||
| U | Intracellular trafficking, secretion, and vesicular transport | ||
| O | Posttranslational modification, protein turnover, chaperones | ||
| Metabolism | |||
| C | Energy production and conversion | ||
| G | Carbohydrate transport and metabolism | ||
| E | Amino acid transport and metabolism | ||
| F | Nucleotide transport and metabolism | ||
| H | Coenzyme transport and metabolism | ||
| I | Lipid transport and metabolism | ||
| P | Inorganic ion transport and metabolism | ||
| Q | Secondary metabolites biosynthesis, transport and catabolism | ||
| Poorly characterized | |||
| R | General function prediction only | ||
| S | Function unknown | ||