Studies on luciferase from Photobacterium phosphoreum. XI. Interaction of 8-substituted FMNH2 with luciferase

J Biochem. 1978 Dec;84(6):1441-6. doi: 10.1093/oxfordjournals.jbchem.a132266.

Abstract

The interaction of bacterial luciferase from Photobacterium phosphoreum with reduced flavin was investigated using various 8-substituted FMNH2 analogs. Flavins tested were FMNH2 and FMNH2 substituted at the 8 position with HO-, CH3O-, C2H5O-, Cl-, Br-, I-, H2N-, (CH3)HN-, and (ch3)2n. 8-ch30-, c2h5o-, cl-, and Br-FMNH2 showed luminescent activity in the luciferase reaction with emission peaks at various wavelengths. 8-HO- and I-FMNH2 were competitive inhibitors toward FMNH2 in the luminescent reaction. 8-Amino analogs of FMNH2 showed no luminescent or inhibitor activity. The dissociation constant of the luciferase-FMNH2 analog complex was determined kinetically as a substrate or inhibitor constant. A contribution of the imino group at position 5 in the isoalloxazine ring to the FMNH2 binding to luciferase was suggested by a Hammett plot of the dissociation constants.

MeSH terms

  • Flavin Mononucleotide / analogs & derivatives*
  • Luciferases / metabolism*
  • Luminescent Measurements
  • Oxidation-Reduction
  • Photobacterium / enzymology*
  • Protein Binding
  • Structure-Activity Relationship

Substances

  • Flavin Mononucleotide
  • Luciferases