Residues photolabeled in a tryptic fragment of Japanese Firefly Luciferase (306-YDLSNLVEIASGGAPLSK-323)a identified by LTQ–FT mass spectrometry and MSMS.

aPhotolabeled residues are indicated in bold.bRepresentative observed masses that include increases due to photolabeling by 3-azioctanol and 7-azioctanol (128 Da) or 3-azibutanol (72 Da) or TFD-benzyl alcohol (188 Da).cAccuracy is the difference between the calculated and observed mass expressed in ppm.dParent peptides are those derived from that fraction of Luciferase in a given run that was not photolabeled during an experiment with azialcohols or TFD-benzyl alcohol. See “Materials and methods” section for other details.