Elongation factors are a set of proteins that are used in protein synthesis in the cell. In the ribosome, they facilitate translational elongation, from the formation of the first peptide bond to the formation of the last one.
Elongation is the most rapid step in translation:
- in prokaryotes it proceeds at a rate of 15 to 20 amino acids added per second (about 60 nucleotides per second)
- in eukaryotes the rate is about two amino acids per second.
Elongation factors play a role in orchestrating the events of this process, and in ensuring the 99.99% accuracy of translation at this speed.
Elongation factors are also a target for pathogen toxins. Corynebacterium diphtheriae produces the diphtheria toxin that alters protein function in the host by inactivating elongation factor (EF-2). This causes pharyngitis and pseudomembranous inflammation in the throat.
See also 
- Prokaryotic elongation factors
- Archaeal elongation factors
- Eukaryotic elongation factors
- GTP-binding elongation factor family, EF-Tu/EF-1A subfamily
- Alberts, B. et al. (2002). Molecular Biology of the Cell, 4th ed. New York: Garland Science. ISBN 0-8153-3218-1
- Berg, J. M. et al. (2002). Biochemistry, 5th ed. New York: W.H. Freeman and Company. ISBN 0-7167-3051-0
- Singh, B. D. (2002). Fundamentals of Genetics, New Delhi, India: Kalyani Publishers. ISBN 81-7663-109-4