title: Independence of the chaperone activity of protein disulfide isomerase from its thioredoxin-like active site.
abstract: Protein disulfide isomerase (PDI) alkylated at thiols of the thioredoxin-like -CHC- active sites is devoid of isomerase activity, but its chaperone-like activity to increase the reactivation yield and prevent the aggregation of guanidine hydrochloride-denatured D-glyceraldehyde-3-phosphate dehydrogenase upon dilution is unimpaired. A peptide of 28 amino acids markedly inhibits both the enzyme and the chaperone activities of PDI. The above results indicate that the -CGHC- active site is necessary for the isomerase activity but not required for the chaperone activity of PDI, whereas the peptide binding site is essential for both activities.
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, Beijing, People's Republic of China.
authors.forename: H
authors.initials: H
authors.lastname: Quan
authors.forename: G
authors.initials: G
authors.lastname: Fan
authors.forename: C C
authors.initials: CC
authors.lastname: Wang
mesh_terms: D000478:Alkylation; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000737:chemistry; D007535:Isomerases / Q000737:chemistry / Q000502:physiology*; D008836:Micrococcal Nuclease / Q000494:pharmacology; D018832:Molecular Chaperones / Q000502:physiology*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000494:pharmacology; D019704:Protein Disulfide-Isomerases; D017510:Protein Folding; D011817:Rabbits; D013329:Structure-Activity Relationship; D013879:Thioredoxins / Q000378:metabolism*
chemical_list: D018832:Molecular Chaperones; D010446:Peptide Fragments; D013879:Thioredoxins; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D008836:Micrococcal Nuclease; D007535:Isomerases; D019704:Protein Disulfide-Isomerases