TCDB: the Transporter Classification Database for membrane transport protein analyses and information

Nucleic Acids Res. 2006 Jan 1;34(Database issue):D181-6. doi: 10.1093/nar/gkj001.


The Transporter Classification Database (TCDB) is a web accessible, curated, relational database containing sequence, classification, structural, functional and evolutionary information about transport systems from a variety of living organisms. TCDB is a curated repository for factual information compiled from >10,000 references, encompassing approximately 3000 representative transporters and putative transporters, classified into >400 families. The transporter classification (TC) system is an International Union of Biochemistry and Molecular Biology approved system of nomenclature for transport protein classification. TCDB is freely accessible at The web interface provides several different methods for accessing the data, including step-by-step access to hierarchical classification, direct search by sequence or TC number and full-text searching. The functional ontology that underlies the database structure facilitates powerful query searches that yield valuable data in a quick and easy way. The TCDB website also offers several tools specifically designed for analyzing the unique characteristics of transport proteins. TCDB not only provides curated information and a tool for classifying newly identified membrane proteins, but also serves as a genome transporter-annotation tool.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Databases, Protein*
  • Humans
  • Internet
  • Membrane Transport Proteins / chemistry
  • Membrane Transport Proteins / classification*
  • Membrane Transport Proteins / physiology
  • Sequence Analysis, Protein
  • User-Computer Interface


  • Membrane Transport Proteins