LIGAND-BINDING PROPERTIES OF THE GLUTATHIONE-BINDING PROTEIN OF THE MUSSEL, MYTILUS-EDULIS

The glutathione-binding protein of Mytilus edulis possesses only one t ryptophan per polypeptide. Quenching of intrinsic fluorescence due to this residue was studied in the presence of glutathione S-transferase ligands; hematin, bilirubin, biliverdin, bromosulphophthalein, 1-anili no-8-naphthalene sulphonate, 1,2-dichloro-4-nitrobenzene, ethacrynic a cid and sodium deoxycholate as well as in the presence of triethyltin bromide. K-d values were estimated from these experiments and were fou nd to be 38-310 mu M. Based on non-denaturing electrophoresis, the pro tein was found to have a native molecular weight of 50 kDa. Taken toge ther with previously reported subunit molecular weights in the region of 25 kDa, this indicates that this protein has a dimeric quaternary s tructure. Copyright (C) 1996 Elsevier Science Inc.