Describe how this enzyme utilizes the following

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Unformatted text preview: of the specificity pocket by removing the methyl group of Thr. This makes the pocket better fit the larger side chain Leu relative to Val. The changes in KM may reflect better binding of Leu and worse binding of Val. 9. Refer to the active site for thermolysin and the general mechanism for the metalloproteases covered in the lecture notes. Describe how this enzyme utilizes the following strategies to accelerate hydrolysis of the substrate: metal ion catalysis, acidbase catalysis, covalent catalysis and/or substrate proximity and orientation. Indicate which, if any, of these are not used by thermolysin. Metal ion catalysis: The enzyme uses a Zn cofactor to bind and activate a water molecule which then acts as a nucleophile. Covalent catalysis: Not present in this mechanism. The enzyme does not form covalent bonds to the substrate. Acid-base catalysis: Glu 143 deprotonates the water molecule to generate a hydroxide nucleophile, which then attacks substrate Proximity and orientation: the enzyme binds two substrates, water and the peptide. The configuration of the active site binds them next to each other and in the right orientation to react productively....
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