Reactivity of glutaredoxins 1, 2 and 3 from Escherichia coli and protein disulfide isomerase towards glutathionyl-mixed disulfides in ribonuclease A.
We have examined the activity of protein disulfide isomerase (PDI) and glutaredoxin (Grx) 1, 2 and 3 from Escherichia coli to catalyze the cleavage of glutathionylated ribonuclease A (RNase-SG) by 1 mM GSH to yield reduced RNase. Apparent Km values for RNase-SG were similar, 2-10 microM, for Grx 1, 3 and PDI but Grx I and Grx 3 showed 500-fold higher turnover numbers than PDI. The atypical Grx 2 also catalyzed deglutathionylation by GSH, but had higher Km and apparent turnover number values compared to the two classical Grx. Refolding of RNase in a glutathione redox buffer was catalyzed by PDI. However, it could be measured only after a characteristic lag phase that was shortened by all three E. coli Grxs in a concentration-dependent manner. A role of the glutaredoxin mechanism in the endoplasmic reticulum is suggested.
Lundström-Ljung
J
J
Medical Nobel Institute of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden. johanna.ljung@mbb.ki.se
Vlamis-Gardikas
A
A
Aslund
F
F
Holmgren
A
A
D001426:Bacterial Proteins / Q000378:metabolism*; D004220:Disulfides / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D054477:Glutaredoxins; D007700:Kinetics; D010084:Oxidation-Reduction; D010088:Oxidoreductases; D019704:Protein Disulfide-Isomerases / Q000378:metabolism*; D017510:Protein Folding; D011506:Proteins / Q000378:metabolism*; D012259:Ribonuclease, Pancreatic / Q000378:metabolism*