Cooperation of ER-60 and BiP in the oxidative refolding of denatured proteins in vitro.

Hirokazu Okudo, Hiroyuki Kato, Yukino Arakaki, Reiko Urade

Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto 611-0011.

Journal of biochemistry 2005 Dec

filter terms:

ER-60 is a PDI family protein that has protein thiol-disulfide oxidoreductase activity. It has been shown to associate with BiP in the endoplasmic reticulum. Here, we analyzed the cooperation of ER-60 and BiP in the oxidative refolding of denatured proteins in vitro. ER-60 facilitated the refolding of 20 or 30% of denatured alpha-lactalbumin or ribonuclease B during incubation for 80 min, and these levels of nearly doubled on the addition of BiP to the reaction mixture. BiP alone could not refold denatured ribonuclease B, but could refold denatured alpha-lactalbumin a little. Enhancement of oxidative refolding of alpha-lactalbumin by ER-60 could be detected only when ER-60 was present from the start of refolding. On surface plasmon resonance analysis, ER-60 was shown to associate with BiP. The association was not influenced by ATP or ADP. Domains a and/or b' of ER-60 were implicated in the association with BiP.

Citation

Hirokazu Okudo, Hiroyuki Kato, Yukino Arakaki, Reiko Urade. Cooperation of ER-60 and BiP in the oxidative refolding of denatured proteins in vitro. Journal of biochemistry. 2005 Dec;138(6):773-80