Open AccessLigand‐Binding Studies on Heavy Riboflavin Synthase of Bacillus subtilis
Author(s) -
BACHER Adelbert,
LUDWIG Heide Carla
Publication year - 1982
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1982.tb06905.x
Subject(s) - protein subunit , stereochemistry , chemistry , stereospecificity , pteridine , ligand (biochemistry) , binding site , bacillus subtilis , atp synthase , moiety , biochemistry , cooperative binding , enzyme , biology , receptor , genetics , bacteria , gene , catalysis
Heavy riboflavin synthase is a complex enzyme consisting of three α subunits and approximately 60 β subunits. Ligand‐binding studies were performed with a variety of substrate and product analogues by analytical ultracentrifugation and by equilibrium dialysis. Nonlinear binding curves indicate the involvement of non‐equivalent binding sites which could be assigned to the α and β subunits by comparison with light riboflavin synthase (subunit composition α 3 ) and with aggregates of isolated β subunits. The β subunit binding site shows a high degree of stereospecificity. Tightly binding ligands must have a ribityl side chain and a pyrimidine or pteridine moiety with polar substituents.