Identification of a lysine residue at a nucleotide binding site in the firefly luciferase with p-fluorosulfonyl[14C]benzoyl-5'-adenosine

Abstract
Firefly [Photinus pyralis] luciferase is 80-90% inactivated within 3 h upon incubation with the adenine nucleotide analogue, p-fluorosulfonylbenzoyl-5''-adenosine (FSBA). Although 4 mol 14C-FSBA/mol enzyme is irreversibly bound during inactivation, only 1 mol of 14C-FSBA appears to be specifically directed to an adenine nucleotide binding site on the enzyme. The other 3 mol of 14C-FSBA is bound to the protein non-specifically. The major radioactive peptide in a tryptic digest of labeled luciferase was isolated and had the amino acid sequence *Lys-Gly-Glx-Asx-Ser-Lys, where *Lys is the radioactive derivative of the lysine residue that was sulfonylated during the inactivation.