Purification and Characterization of N-β-Alanyl-5-S-glutathionyl-3,4-dihydroxyphenylalanine, a Novel Antibacterial Substance of Sarcophaga peregrina (Flesh Fly)

• DOI: 10.1074/jbc.271.23.13573
• Publication Date: 2002-07-26T15:15:23Z
• Authors: Jae Yoon Leem; Chiaki Nishimura; Shoichiro Kurata; Ichio Shimada; Ayako Kobayashi; Shunji Natori
• Keywords: 0301 basic medicine; 03 medical and health sciences; Molecular Structure; Diptera; Escherichia coli; Animals; Immunization; Hydrogen Peroxide; Glutathione; Anti-Bacterial Agents; Dihydroxyphenylalanine; 3. Good health

We purified a novel antibacterial substance from immunized adult Sarcophaga and determined its molecular structure to be N-beta-alanyl-5-S-glutathionyl-3,4-dihydroxyphenylalanine (5-S-GAD). We synthesized 5-S-GAD enzymatically from N-beta-alanyl-3, 4-dihydroxyphenylalanine (beta-Ala-Dopa) and reduced glutathione (GSH). The antibacterial activity of 5-S-GAD was found to be due to its production of H2O2. This is a novel antibacterial mechanism as it differs from the mechanisms of known antibacterial peptides. Two possible roles of 5-S-GAD in insect immunity, suppression of bacterial growth and activation of a Rel family transcription factor, are proposed.