PSORT is a computer program for the prediction of protein localization sites in cells. It receives the information of an amino acid sequence and its source orgin, e.g., Gram-negative bacteria, as inputs. Then, it analyzes the input sequence by applying the stored rules for various sequence features of known protein sorting signals. Finally, it reports the possiblity for the input protein to be localized at each candidate site with additional information.

PSORT is mirrored at Tokyo, Okazaki, and Peking


WoLF PSORT (an update of PSORT II for fungi/animal/plant sequences)

WoLF PSORT Prediction

PSORT II (Recommended for animal/yeast sequences)

PSORT II Users' Manual
PSORT II Prediction

PSORT (Old version; for bacterial/plant sequences)

PSORT Users' Manual (WWW version)
PSORT Prediction

iPSORT (Detection of N-terminal sorting signals)

iPSORT Prediction
How to Obtain iPSORT (caml-iPSORT)

PSORT-B (Recommended for Gram-negative bacteria)

PSORT-B Prediction

Other Information

PSORT Bibliography
PSORT Users' Manual (e-mail version)

PSORT program was coded by: Kenta Nakai, Ph.D., Human Genome Center, Institute for Medical Science, University ot Tokyo, Japan ( Binary program for Sun/Solaris OS is freely available upon request.

PSORT II is based on the collaboration with Paul Horton ( PSORT II based on the SWISS-PROT data is freely distributed under the GNU General Public License agreement. Send e-mail to: to get a copy.

iPSORT is based on the collaboration with Hideo Bannai (IMS, U. Tokyo; now: Kyushu Univ.), Yoshinori Tamada (IMS, U. Tokyo), Osamu Maruyama (Kyushu U.), and Satoru Miyano (IMS, U. Tokyo). A version of iPSORT, written in the OCaml language, is distributed freely upon request. Contact Bannai for details.

PSORT-B, a program applicable to the sequences of Gram-negative bacteria, is available at the new portal site ( maintained by Fiona Brinkman's laboratory, Simon Fraser U., Canada since July, 2003.

WoLF PSORT, is developed and served by Paul Horton et al. (in collaboration with K. Nakai) at CBRC, AIST, JAPAN since April, 2005.

YPD<TM> localization information and title lines are provided by courtesy of Incyte Genomics, Inc. SWISS-PROT is now maintained by the EMBL and the Swiss Institute of Bioinformatics (SIB).

Special thanks to Minoru Kanehisa for support, to Toshiyuki Okumura, Toshiki Ohkawa, and Tomoki Miwa for technical assistance, and to Amos Bairoch and the people of Incyte Genomics, Inc. for the allowance of integrating an excerpt of SWISS-PROT and YPD<TM>, respectively. The mirror server at Peking is maintained by Yunjia Chen and Jingchu Luo (Thanks!).

Last update: January 5, 2007