The serine protease inhibitor family from Ascaris suum: chemical determination of the five disulfide bridges.
Chymotrypsin/elastase inhibitor-1 is a member of the Ascaris family of serine protease inhibitors. It is characterized by five disulfide bridges in a polypeptide chain of 63 amino acids. The disulfide bridge pairing was resolved by cleavage at methionyl residues with cyanogen bromide followed by a combination of proteolytic digestions with glycyl endopeptidase, Staphylococcal serine proteinase, and submandibular proteinase A. The peptides were separated on a reverse-phase HPLC column. Amino acid analyses and N-terminal microsequencing of the cystine containing peptides revealed the disulfide bridge pairing between residues 5-54, 15-29, 18-38, 22-33, and 40-60. The disulfide bridge pairing of other members of this unique family was also assigned. The major isoform, trypsin inhibitor-1, and chymotrypsin/elastase inhibitor-4 share the same disulfide bridge pattern. These results strongly suggest that all members of the Ascaris family of serine protease inhibitors have the same disulfide bridge pattern which represents a unique motif.
Department of Biochemistry and Molecular Biology, University of South Dakota School of Medicine, Vermillion 57069-2390.
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Bernard
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Peanasky
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D017165:Ascaris suum / Q000737:chemistry*; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism; D002918:Chymotrypsin / Q000037:antagonists & inhibitors; D003488:Cyanogen Bromide; D004220:Disulfides / Q000737:chemistry*; D008715:Methionine / Q000737:chemistry; D008969:Molecular Sequence Data; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors; D010446:Peptide Fragments / Q000302:isolation & purification / Q000378:metabolism; D012697:Serine Endopeptidases / Q000378:metabolism; D015842:Serine Proteinase Inhibitors / Q000737:chemistry* / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000737:chemistry / Q000378:metabolism
D000596:Amino Acids; D004220:Disulfides; D010446:Peptide Fragments; D015842:Serine Proteinase Inhibitors; D014361:Trypsin Inhibitors; D008715:Methionine; D012697:Serine Endopeptidases; D002918:Chymotrypsin; C028344:glutamyl endopeptidase; D010196:Pancreatic Elastase; C022325:aspartic proteinase A; D016282:Aspartic Acid Endopeptidases; D003488:Cyanogen Bromide