Team:Imperial College London/Stomach

From 2009.igem.org

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The stomach serves to break large proteins into peptides. These peptides are then broken down into amino acids once they enter the duodenum.
The stomach serves to break large proteins into peptides. These peptides are then broken down into amino acids once they enter the duodenum.
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* Pepsin = stomach
 
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* Trypsin = duodenum
 
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* Chymotrypsin
 
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* Carboxypeptidase
 
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==Duodenum==
 
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[[Image:duodenum.png|100px|left]]
 
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Endopeptidases (trypsin, chymotryopsin, elastase)
 
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Exopeptidases (carboxypeptidases A & B)
 
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Enteropeptidase
 
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<div id='sib_container'>
 
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  <form method=POST action="http://www.expasy.ch/cgi-bin/peptidecutter/peptidecutter.pl" target="_blank">
 
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  <textarea name="protein" rows=5 cols=50>Met S T A V L E N P G L G R K L S D F G Q E T S Y I E D N C N Q N G A I S L I F S L K E E V G A L A K V L R L F E E N D V N L T H I E S R P S R L K K D E Y E F F T H L D K R S L P A L T N I I K I L R H D I G A T V H E L S R D K K K D T V P W F P R T I Q E L D R F A N Q I L S Y G A E L D A D H P G F K D P V Y R A R R K Q F A D I A Y N Y R H G Q P I P R V E Y Met E E E K K T W G T V F K T L K S L Y K T H A C Y E Y N H I F P L L E K Y C G F H E D N I P Q L E D V S Q F L Q T C T G F R L R P V A G L L S S R D F L G G L A F R V F H C T Q Y I R H G S K P Met Y T P E P D I C H E L L G H V P L F S D R S F A Q F S Q E I G L A S L G A P D E Y I E K L A T I Y W F T V E F G L C K Q G D S I K A Y G A G L L S S F G E L Q Y C L S E K P K L L P L E L E K T A I Q N Y T V T E F Q P L Y Y V A E S F N D A K E K V R N F A A T I P R P F S V R Y D P Y T Q R I E V L D N T Q Q L K I L A D S I N S E I G I L C S A L Q K I K Stop</textarea>
 
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  <input type="submit" value="Perform">
 
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  <input type=hidden name=enzyme_number value= less_enzymes checked>
 
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  <input type=hidden name=enzyme  value=Ch_hi checked>
 
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  <input type=hidden name=enzyme  value=Ch_lo checked>
 
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  <input type=hidden name=enzyme  value=Tryps checked>
 
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  <input type=hidden name=enzyme value=Enter checked>
 
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  <input type=hidden checked name=cleavage_map value=cleavage_map>
 
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<select name="block_size"  size=1 style="display:none">
 
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  <option selected value= "60" selected>
 
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  <input type=hidden name=alphtable checked value=alphtable>
 
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  <input type=hidden name=cleave_number checked value=all>
 
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<br><A HREF="http://www.expasy.ch/tools/peptidecutter/tools/peptidecutter/peptidecutter_references.html">references</A> /<A HREF="http://www.expasy.ch/tools/peptidecutter/tools/peptidecutter/peptidecutter_instructions.html">documentation</A>
 
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<div id = 'sib_footer'> </div>
 
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===Trypsin===
 
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* Trypsin is found in the duodenum and serves to hydrolyse peptides into amino acids.
 
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* Trypsin has an optimal operating pH of ~8 and an optimum temperature of 37°C.
 
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* Trypsin breaks down the milk protein casein. For this reason, milk protein would be a good protein to use for secondary encapsulation.
 
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===Chymotryopsin===
 
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===Elastase===
 
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===Enterokinase===
 
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===Carboxypeptidases A & B===
 
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{{Imperial/09/Division}}
 
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Small Intestine = Aminopeptidase N
 
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Dipeptidyl aminopeptidase IV
 
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Aminopeptidase P
 
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Carboxypeptidase P
 
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Angotensin-converting enzyme
 
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Glutamyl aminopeptidase
 
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{{Imperial/09/Division}}
 
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===Small Intestine===
 
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{{Imperial/09/Division}}
 
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===Large Intestine===
 
{{Imperial/09/TemplateBottom}}
{{Imperial/09/TemplateBottom}}

Revision as of 10:21, 12 October 2009

Human Digestive Proteases:

Digestivesystem.jpg

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


Stomach

The stomach is the first point at which polypeptides are broken down. The low pH of the stomach causes enzymes to denature. The process of denaturation opens proteins up to attack from proteases.

Pepsin

Pepsin is a powerful protease that cleaves at the N-terminus after aromatic amino acids such as phenylalanine, tryptophan, and tyrosine. The optimum pH of pepsin is from 1.5 to 2, at a pH of above 5 denaturation occurs. This means that pepsin is only functional in the acidic environment of the stomach.

One of the enzymes that we are showcasing is phenylalanine hydroxylase (PAH) (as a treatment for PKU). If this enzyme was simply swallowed in an unencapsulated form it would be cleaved in 146 places by pepsin in the stomach.

Click on the perform button to see a simulated digestion of PAH by pepsin. Alternativly, paste in your own sequence to see if it would be a good candidate for encapsulation.


references /documentation


Mr. Gene   Geneart   Clontech   Giant Microbes

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