title: Peptides derived from human C-reactive protein inhibit the enzymatic activities of human leukocyte elastase and cathepsin G: use of overlapping peptide sequences to identify a unique inhibitor.
abstract: Ten overlapping 15-mer peptides, spanning the entire inner disulfide loop of human C-reactive protein (residues 36-97), were used to isolate a potent inhibitor of the enzymes human leukocyte elastase and human leukocyte cathepsin G, which are associated with chronic inflammatory tissue damage. In contrast to the inability of intact C-reactive protein to inhibit both enzymes, the synthetic peptide E62ILIFWSKDIGYSFT76 inhibited leukocyte elastase (Ki = 0.18 microM) and cathepsin G (Ki = 0.25 microM) at concentrations far lower than the acute-phase concentration of C-reactive protein. Several peptide-enzyme binding motifs were elucidated by structure-function studies, with the Glu62 residue being crucial in establishing long-range subsite interactions. Peptides derived from C-reactive protein, which may be generated in vivo by neutrophil-mediated proteolysis as part of a complex regulatory homeostatic mechanism, may play an important role in regulating the activity of matrix-degrading enzymes, specifically at sites of inflammation. The present results thus may shed additional insight on the physiological functions of the major acute-phase reactant C-reactive protein, and perhaps be used as a basis for the design of novel therapeutic substances.
authors.affiliation: Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot, Israel.
authors.forename: E J
authors.initials: EJ
authors.lastname: Yavin
authors.forename: M
authors.initials: M
authors.lastname: Fridkin
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology*; D056649:Cathepsin G; D002403:Cathepsins / Q000037:antagonists & inhibitors*; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000494:pharmacology*; D006801:Humans; D008969:Molecular Sequence Data; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors*; D010455:Peptides / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology*; D017421:Sequence Analysis; D012697:Serine Endopeptidases; D013379:Substrate Specificity
chemical_list: D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D010455:Peptides; C020723:citrate-binding transport protein; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; D010196:Pancreatic Elastase