Encyclopedia of Systems Biology

2013 Edition
| Editors: Werner Dubitzky, Olaf Wolkenhauer, Kwang-Hyun Cho, Hiroki Yokota

Protein-Protein Interaction Networks

  • Long Jason Lu
  • Minlu Zhang
Reference work entry
DOI: https://doi.org/10.1007/978-1-4419-9863-7_878



A protein-protein interaction (PPI) network is a network or graph representation of physical interactions between protein pairs in an organism. In the network, each node/vertex represents a protein and each edge/link represents an interaction. The network is undirected, usually simple (which means maximally only one edge is allowed between two proteins), and allows self-loops (which indicates interactions between the same protein). PPIs can be determined by small- or large-scale experiments such as the yeast-two-hybrid screens or tandem affinity purification experiments, computational predictions such as interolog mapping, multimeric threading or machine learning, and expert curations (Xia et al. 2004).



  1. Xia Y, Yu H, Jansen R, Seringhaus M, Baxter S et al (2004) Analyzing cellular biochemistry in terms of molecular networks. Annu Rev Biochem 73:1051–1087PubMedGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2013

Authors and Affiliations

  1. 1.Division of Biomedical InformaticsCincinnati Children’s Hospital Research FoundationCincinnatiUSA
  2. 2.Department of Computer ScienceUniversity of CincinnatiCincinnatiUSA