pepsinogen and prorennin are converted to the active forms pepsin and rennin by HCl whereas trypsinogen is converted to trypsin by enterokinase, an enzyme found in intestinal juice.
*Rennin simply catalyses the conversion of caesinogen(soluble milk protein) to caesin(insoluble milk protein) so that it stays in the stomach longer for pepsin to digest.
The digestion of proteins is as follows:
PROTEINS
(Made of one or a few polypeptide chains,
where each polypeptide chain is made of a few hundred amino acids
linked by peptide bonds)
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Broken down by PEPSIN (in Stomach)
and TRYPSIN (in Duodenum)
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V
PEPTONES/PEPTIDES
polypeptides can be considered as peptides.
(Made of tens of amino acids linked by peptide bonds,
ie, shorter chains of amino acids)
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Broken down by EREPSIN (in Small Intestine)
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V
AMINO ACIDS
(Which are small enough to be absorbed by the epithelial cells on the villi)
(Made of one or a few polypeptide chains,
where each polypeptide chain is made of a few hundred amino acids
linked by peptide bonds)
|
|
Broken down by PEPSIN (in Stomach)
and TRYPSIN (in Duodenum)
|
|
V
PEPTONES/PEPTIDES
polypeptides can be considered as peptides.
(Made of tens of amino acids linked by peptide bonds,
ie, shorter chains of amino acids)
|
|
Broken down by EREPSIN (in Small Intestine)
|
|
V
AMINO ACIDS
(Which are small enough to be absorbed by the epithelial cells on the villi)
2 comments:
what do you mean by "all three enzymes are produced in the inactive form (pepsinogen, trypsinogen, and prorennin)." ?
i dont really understand that part. please explain. thank you =)
Hi,
The 3 protease that work on proteins are produced in the inactive form. Pepsin is produced as pepsinogen, rennin is produced as prorennin and trypsin from the pancreas is produced as trypsinogen. They are produced as inactive enzymes to prevent the hydrolysis of the proteins in the cells that line the stomach/small intestine that will cause destruction of the cells. Enterokinase converts trypsinogen to trypsin and erepsin works on peptones, so there is no need for them to be produced in the inactive form. Hope this answers your question. Do leave your name and class in future.
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