pHluorinSE is a pH-sensitive fluorescent protein. It is an artificial derivative of the naturally occurring fluorescent protein encoded by the Aequorea victoria GFP gene (UniProtKB:P42212), containing the mutations found in pHluorinE (S147D, N149Q, T161I, V163A, S175G, S202F, Q204T and A206T), plus two additional mutations (F64L and S65T) that red-shift the excitation peak of the ecliptic wavelength band from 475nm to 491nm and increase its fluorescence 5.9-fold (FBrf0152271).