Team:Imperial College London/Stomach

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Contents

Human Digestive Proteases:

The stomach serves to break large proteins into peptides. These peptides are then broken down into amino acids once they enter the duodenum.


  • Pepsin = stomach
  • Trypsin = duodenum
  • Chymotrypsin
  • Carboxypeptidase



Stomach

The stomach is the first point at which polypeptides are broken down. The low pH of the stomach causes enzymes to denature, opening them up to attack from proteases such as pepsin.

Pepsin

  • Released by chief cells in the stomach.
  • Expressed as a zymogen pepsinogen.
  • Pepsinogen is converted to pepsin by HCl which is released by parietal cells of the stomach.
  • Cleaves at the N-terminus after aromatic amino acids such as phenylalanine, tryptophan, and tyrosine.
  • Optimum pH of 1.5 to 2. Pepsin denatures when the pH is more than 5.0.



Peptide cutter

PeptideCutter [references / documentation] predicts potential cleavage sites cleaved by proteases or chemicals in a given protein sequence. PeptideCutter returns the query sequence with the possible cleavage sites mapped on it and /or a table of cleavage site positions.

Enter a UniProtKB (Swiss-Prot or TrEMBL) protein identifier, ID (e.g. ALBU_HUMAN), or accession number, AC (e.g. P04406), or an amino acid sequence (e.g. 'SERVELAT'):

the cleavage of the protein. the fields.

Please, select
 only the following selection of enzymes and chemicals for the following enzymes an additional, more sophisticated model can be applied that attributes a probability of cleavage to each site :


Please enter the lowest cleavage probability that you would like to be displayed: %

Please indicate the way you would like the cleavage sites to be displayed

Map of cleavage sites. Please select the number of amino acid within one block:
Table of sites, sorted alphabetically by enzyme and chemical name
Table of sites, sorted sequentially by amino acid number


Please indicate which enzymes to include in the display

All enzymes and chemicals
Enzymes and chemicals cleaving exactly times
Enzymes and chemicals cleaving at least times, and at most times

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