Cyclophilin active site mutants have native prolyl isomerase activity with a protein substrate.

Journal Article (Journal Article)

The prolyl isomerase activity of cyclophilins is traditionally measured by an assay in which prolyl cis/trans isomerization in a chromogenic tetrapeptide is coupled with its isomer-specific cleavage by chymotrypsin. Two variants of mitochondrial cyclophilin with substitutions in the presumed active site (R73A and H144Q) are inactive in the protease-coupled assay, but show almost wild-type activity in an assay that is based on the catalysis of a proline-limited protein folding reaction. This prolyl isomerase assay is preferable, both because coupling with proteolysis is avoided and because an intact protein instead of a short peptide is used as a substrate. Possibly, some earlier conclusions about the catalytic mechanism and the involvement of the prolyl isomerase activity in the cellular function of immunophilins may need reevaluation.

Full Text

Duke Authors

Cited Authors

  • Scholz, C; Schindler, T; Dolinski, K; Heitman, J; Schmid, FX

Published Date

  • September 1, 1997

Published In

Volume / Issue

  • 414 / 1

Start / End Page

  • 69 - 73

PubMed ID

  • 9305734

International Standard Serial Number (ISSN)

  • 0014-5793

Digital Object Identifier (DOI)

  • 10.1016/s0014-5793(97)00979-4


  • eng

Conference Location

  • England