Comparison List


CyPet is a basic (constitutively fluorescent) cyan fluorescent protein published in 2005, derived from Aequorea victoria. It has moderate acid sensitivity.
Oligomerization Organism Molecular Weight Cofactor
Weak dimer Aequorea victoria 26.9 kDa -

FPbase ID: V534T


Ex λ Em λ EC (M-1 cm-1) QY Brightness pKa Maturation (min) Lifetime (ns)
435 477 35,000 0.51 17.85 5.02    

CyPet OSER Measurements

% Normal Cells OSER/NE ratio Cell Type Reference
94.0 ± 2.4 (10000 cells) - HeLa Cranfill et al. (2016)


No photostability measurements available ... add one!

CyPet Sequence

CyPet was derived from ECFP with the following mutations: T9G/V11I/D19E/A87V/I167A/E172T/L194I/L231H
amino acid numbers relative to avGFP. show relative to ECFP



Nguyen and Daugherty (2005) reported the development of an improved FRET pair, YPet & CyPet, which had a sevenfold enhancement of the FRET signal. However, we discovered that most of the signal enhancement was due to enhanced dimerization of YPet to CyPet within the tethered construct, and was substantially reduced when we incorporated the monomerizing mutation previously developed to prevent the weak dimerization of GFP (Zacharias et al. 2002).

Ohashi et al. (2007)

Primary Reference

Evolutionary optimization of fluorescent proteins for intracellular FRET

Nguyen Aw, Daugherty Ps

(2005). Nature Biotechnology, 23(3) , 355-360. doi: 10.1038/nbt1066. Article   Pubmed

Additional References

External Resources

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