GroEL protects the sarcoplasmic reticulum Ca(++)-dependent ATPase from inactivation in vitro

M U Javed, F Michelangeli, P A Lund

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


The molecular chaperone, GroEL, facilitates correct protein folding and inhibits protein aggregation. The function of GroEL is often, though not invariably, dependent on the co-chaperone, GroES, and ATP. In this study it is shown that GroEL alone substantially reduces the inactivation of purified Ca(++)-ATPase from rabbit skeletal muscle sarcoplasmic reticulum. In the absence of GroEL, the enzyme became completely inactive in about 45-60 hours when kept at 25 degrees C, while in the presence of an equimolar amount of GroEL, the enzyme remained approximately 80% active even after 75 hours. Equimolar amounts of BSA or lysozyme were unable to protect the enzyme from inactivation under identical conditions. Analysis by SDS-PAGE showed GroEL was acting by blocking the aggregation of ATPase at 25 degrees C. GroEL was not as effective in protection at -20 degrees C or 4 degrees C. These results are discussed in the context of current models of the GroEL mechanism.
Original languageEnglish
Pages (from-to)631-8
Number of pages8
JournalBiochemistry and molecular biology international
Issue number4
Publication statusPublished - Apr 1999


  • Animals
  • Enzyme Activation
  • Chaperonin 60
  • Calcium-Transporting ATPases
  • Sarcoplasmic Reticulum
  • Rabbits


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