Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.25 (chymopapain)
 430 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The complete amino acid sequence of the cysteine proteinase inhibitor from potato tubers was determined. The inhibitor is a single-chain protein having 180 amino acid residues. Its primary structure was elucidated by automatic degradation of the intact protein and sequence analysis of peptides generated by CNBr, trypsin and glycyl endopeptidase. A search through the protein sequence database showed homology to other plant proteinase inhibitors of different specificities and non-inhibitory proteins of M(r) around 20,000. On the basis of sequence homology, prediction of secondary structure and fold compatibility, based on a 3D-1D score to the three-dimensional profile of Erythrina caffra trypsin inhibitor, we suggest that the potato cysteine proteinase inhibitor belongs to the superfamily of proteins that have the same pattern of three-dimensional structure as soybean trypsin inhibitor. This superfamily would therefore include proteins that inhibit three different classes of proteinases-serine, cysteine and aspartic proteinases.
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PMID:The primary structure of inhibitor of cysteine proteinases from potato. 822 55

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.
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PMID:The serine protease inhibitor family from Ascaris suum: chemical determination of the five disulfide bridges. 851 22