Sandbox 31: Difference between revisions
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The active site of papain has a <scene name='Sandbox_31/Activesite/1'>"Catalytic Triad"</scene>including CYS 25, HIS 159, and ASN 175. | The active site of papain has a <scene name='Sandbox_31/Activesite/1'>"Catalytic Triad"</scene>including CYS 25, HIS 159, and ASN 175. | ||
[[Image:papain2.jpg]] This triad interacts with the substrate to catalyze the reaction. The sulfur from CYS 25 attacks the backbone amine on the substrate forming a tetrahedral intermediate. Next, the carbonyl is reformed and the carbon nitrogen bond is broken. A water associated with a nitrogen on HIS 159 then attacks the carbonyl forming a second tetrahedral intermediate. The carbonyl then reforms breaking the carbon-sulfur bond. This leaves a carboxy group on the end of one piece of the substrate and an amino group on the end of the other piece. | [[Image:papain2.jpg]] | ||
This triad interacts with the substrate to catalyze the reaction. The sulfur from CYS 25 attacks the backbone amine on the substrate forming a tetrahedral intermediate. Next, the carbonyl is reformed and the carbon nitrogen bond is broken. A water associated with a nitrogen on HIS 159 then attacks the carbonyl forming a second tetrahedral intermediate. The carbonyl then reforms breaking the carbon-sulfur bond. This leaves a carboxy group on the end of one piece of the substrate and an amino group on the end of the other piece. | |||
[[Image:mechanism.jpg]] | |||
==Inhibitors== | |||
There are many inhibitors of cysteine proteases like papain, including antipain, cystatin, | There are many inhibitors of cysteine proteases like papain, including antipain, cystatin, | ||
<scene name='Sandbox_31/1popligand_contacts/1'>TextToBeDisplayed</scene> | <scene name='Sandbox_31/1popligand_contacts/1'>TextToBeDisplayed</scene> | ||
