Bovine liver thiol-protein disulphide oxidoreductases. An alternative method for differential purification and resolution of protein disulphide-isomerase and glutathione-insulin transhydrogenase.
1. Protein disulphide-isomerase (EC 5.3.4.1) and glutathione-insulin transhydrogenase (EC 1.8.4.2) activities in bovine liver were studied in parallel during purification of 'thiol-protein disulphide oxidoreductase' by the procedure of Carmichael, Morin & Dixon [(1977) J Biol. Chem. 252, 7163-7167]. The two activities showed no quantitative co-purification and were partially resolved by (NH4)SO4 precipitation, indicating that distinct enzymes are present. 2. Protein disulphide-isomerase was purified by a relatively rapid method involving a combination of the early stages of the Carmichael procedure and covalent chromatography, with a new stepwise elution procedure. Ion-exchange chromatography yields a homogeneous preparation of mol.wt. 57 000. 3. The relationship between protein disulphide-isomerase, glutathione-insulin transhydrogenase and 'thiol-protein disulphide oxidoreductase' is discussed.
D000818:Animals; D002417:Cattle; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004220:Disulfides / Q000302:isolation & purification; D007535:Isomerases / Q000302:isolation & purification*; D008099:Liver / Q000201:enzymology; D010088:Oxidoreductases / Q000302:isolation & purification*; D011490:Protein Disulfide Reductase (Glutathione) / Q000302:isolation & purification*; D019704:Protein Disulfide-Isomerases
D004220:Disulfides; D010088:Oxidoreductases; D011490:Protein Disulfide Reductase (Glutathione); D007535:Isomerases; D019704:Protein Disulfide-Isomerases