scholarly journals Thiol-protein disulphide oxidoreductases. Differences between protein disulphide-isomerase and glutathione-insulin transhydrogenase activities in ox liver

1976 ◽  
Vol 159 (2) ◽  
pp. 385-393 ◽  
Author(s):  
H C Hawkins ◽  
R B Freedman
Keyword(s):  
High Resolution ◽  
Ion Exchange ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Heat Denaturation ◽  
Differential Centrifugation ◽  
Protein Disulphide Isomerase ◽  
Final Sample ◽  
Thiol Protein ◽  
Single Enzyme

1. Protein disulphide-isomerase and glutathione-insulin transhydrogenase activities were assayed in parallel through a conventional purification of protein disulphide-isomerase from ox liver. 2. Throughout a series of purification steps (differential centrifugation, acetone extraction, (NH4)2SO4 precipitation and ion-exchange chromatography), the two activities appeared in the same fractions but were purified to different extents. 3. The final sample was 143-fold purified in protein disulphide-isomerase but only 10-fold purified in glutathione-insulin transhydrogenase; nevertheless the two activities in this preparation were not resolved by high-resolution isoelectric focusing and both showed pI4.65. 4. In a partially purified preparation containing both activities, glutathione-insulin transhydrogenase was far more sensitive to heat denaturation than was protein disulphide-isomerase; conversely protein disulphide-isomerase was more sensitive to inactivation by deoxycholate. 5. The data are inconsistent with a single enzyme being responsible for all the protein disulphide-isomerase and glutathione-insulin transhydrogenase activity of ox liver. It is suggested that several similiar thiol-protein disulphide oxidoreductases of overlapping specificities may better account for the data.

scholarly journals Bovine liver thiol-protein disulphide oxidoreductases. An alternative method for differential purification and resolution of protein disulphide-isomerase and glutathione-insulin transhydrogenase

1980 ◽  
Vol 191 (2) ◽  
pp. 389-393 ◽  
Author(s):  
D A Hillson ◽  
R B Freedman
Keyword(s):  
Ion Exchange ◽  
Rapid Method ◽  
Bovine Liver ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Protein Disulphide Isomerase ◽  
The Relationship ◽  
Thiol Protein ◽  
Homogeneous Preparation ◽  
Covalent Chromatography

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.

High-resolution determination of 147Pm in urine using dynamic ion-exchange chromatography

1992 ◽  
Vol 64 (20) ◽  
pp. 2339-2343 ◽  
Author(s):  
Steve. Elchuk ◽  
Charles A. Lucy ◽  
Kerry I. Burns
Keyword(s):  
High Resolution ◽  
Ion Exchange ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography

Studies on salivary and pancreatic lipases of the pre-ruminant calf

1982 ◽  
Vol 49 (3) ◽  
pp. 347-360 ◽  
Author(s):  
Joyce Toothill
Keyword(s):  
Ion Exchange ◽  
Affinity Chromatography ◽  
Pancreatic Lipase ◽  
Lipase Activity ◽  
Lipolytic Activity ◽  
Gel Filtration ◽  
Ion Exchange Chromatography ◽  
Maximum Activity ◽  
Exchange Chromatography ◽  
Single Enzyme

SUMMARYSalivary and pancreatic lipases of the pre-ruminant calf have been studied using ion-exchange chromatography and gel filtration. In addition, pancreatic lipase has been fractionated using concanavalin A-affinity chromatography. The effects of 5,5′-dithiobis(2-nitrobenzoic acid), organic solvents and trypsin on pancreatic lipase have also been investigated. The effect of taurodeoxycholate on the lipolytic activity of the 2 lipases has been compared. Salivary lipase behaved as a single enzyme on ion-exchange chromatography, and gel filtration gave a mol. wt value of 52000 for the enzyme. Although pancreatic lipase appeared to be a single enzyme on gel filtration, with a mol. wt of almost 80000, the lipase was shown by ion-exchange and affinity chromatography to consist of at least 2 enzymes of mol. wts 72000 and 60000, and did not require colipase for maximum activity in the presence of high concentrations of bile salts. Colipase-dependent lipase, mol. wt about 45000, and probably amounting to not more than 10% of the total activity, was also present. This was the predominant form only after large losses in total lipolytic activity had occurred, as after treatment with a mixture of ether, ethanol and deoxycholate, or prolonged action of trypsin. When the concentration of taurodeoxycholate was increased from zero to 1 mM in a tributyrin substrate, the lipolytic activites of calf salivary and pancreatic lipases, and pig pancreatic lipase, increased. At a concentration of 4 mM-taurodeoxycholate, calf salivary lipase activity was higher, that of calf pancreatic lipase slightly lower and pig pancreatic lipase activity markedly lower.

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