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Specialty Chemistry Forums => Biochemistry and Chemical Biology Forum => Topic started by: puzzled on April 01, 2005, 09:56:39 PM

Title: Gas Gangrene
Post by: puzzled on April 01, 2005, 09:56:39 PM
Gas gangrene is caused by the anerobic bacteria, Clostridium perfringens.  This bacteria causes massive tissue destruction.  One of the enzymes that it secretes cleaves preferentially at the Y-Gly bond in the sequence Proline-Tyrosine-Glycine-Proline, where Tyrosine is most frequently a neutral amino acid.  

P-Y-G-P- -----> -P-Y-COO(-) + (+)NH3-G-P-

Propose why the enzyme doesn't affect the bacteria itself.  I'm thinking...because the enzyme doesn't lose any atoms?  I have no idea, and the websites I find only explain about gas gangrene itself and doesn't lead me to an answer.
Title: Re:Gas Gangrene
Post by: Donaldson Tan on April 02, 2005, 04:50:35 PM
the enzyme mechanism follows the lock-and-key hypothesis. i think you gotta examine the active site on the gangrene enzyme to see why it likes to attack the Y-site.
Title: Re:Gas Gangrene
Post by: puzzled on April 02, 2005, 08:36:55 PM
Thanks!  I got the idea now!
Title: Re:Gas Gangrene
Post by: AWK on April 04, 2005, 05:05:19 AM
Bacteria may produce many substances that inhibit auto-destruction
Title: Re:Gas Gangrene
Post by: Donaldson Tan on April 04, 2005, 07:38:10 AM
alternatively, the enzyme that causes tissue destruction exists in its de-activated form inside the bacteria. it requires a co-enzyme to activate it before it can attack its specific amino acid residual site. the co-enzyme and enzyme are most probably stored in different vesicles in the bacteria before both are released (secreted) together into the host body.

btw this seems more like a biology question. i will move it to the "chemical biology" section.