BCH 3125 Lecture Notes - Lecture 4: Acetylcholinesterase, Serine Protease, Covalent Bond
24 Sep 2017
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Document Summary
A family of digestive enzymes that catalyze the hydrolysis of peptide bonds. How do they do this: going back to the relationship between rate enhancement and g . The amount by which an enzyme lowers the activation energy by 10-fold is -5. 71 kj/mol. The first step in assessing the mechanism of function of any protein is to develop a method for measuring that function. Serine proteases hydrolyze peptide and ester bonds, such that found in p-nitrophenylacetate (p-npa): hydrolysis of n-npa leads to the production of p-nitrophenolate (p-np) which absorbs strongly at 450nm. Measuring reaction rate (velocity: add p-npa, at time = 0, add enzyme, follow the rate of product (p-np) formation by measuring the a450. The increase in a450 with time can be converted directly into the increase of [p-np] A typical enzyme catalyzed reaction is linear at the start (i. e. 0). This biphasic behavior tells us that the reaction has 2 steps.
