Abstract
A luminally located peptidyl prolyl cis-trans-isomerase (PPI) has been purified from bovine liver microsomes. It has a molecular mass of 20.6 kDa, and N-terminal sequencing demonstrates strong sequence similarity to the sequences of the cyclophilin B family. The enzyme catalyses the isomerization of the standard proline-containing peptide N-succinyl-Ala-Ala-Pro-Phe p-nitroanilide, as well as the refolding of RNAase T1. Kinetic properties, substrate-specificity data and inhibition by cyclosporin A indicate that it is a cyclophilin-type PPI, consistent with the amino-acid-sequence results.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Isomerases / antagonists & inhibitors
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Amino Acid Isomerases / immunology
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Amino Acid Isomerases / isolation & purification*
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Amino Acid Sequence
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Animals
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Blotting, Western
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Carrier Proteins / antagonists & inhibitors
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Carrier Proteins / immunology
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Carrier Proteins / isolation & purification*
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Cattle
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Cyclosporine / pharmacology
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Endoplasmic Reticulum / enzymology*
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Kinetics
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Molecular Sequence Data
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Peptidylprolyl Isomerase
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Protein Conformation
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Substrate Specificity
Substances
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Carrier Proteins
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Cyclosporine
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Amino Acid Isomerases
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Peptidylprolyl Isomerase