PAmCherry1 is a monomeric photoactivatable red fluorescent protein. It is irreversibly converted from a dark state to a red fluorescent protein upon irradiation with a pulse of violet light of peak activation wavelength 404nm. The red fluorescent form has an excitation peak of 564nm and an emission peak of 595nm in vitro. PAmCherry1 was derived by mutagenesis of mCherry (PMID:19169259).