Lab Report C.1.pdf - Enzyme Kinetics Characterization...

This preview shows page 1 - 4 out of 15 pages.

Enzyme Kinetics Characterization: Alcohol Dehydrogenase By Raymond Samuel September 26, 2017 Partner Zach Patel Instructor: Dr. Dennis Brown1
Abstract: This experiment involved the analysis of the kinetics of the enzyme alcohol dehydrogenase under different conditions such as substrate concentration, temperature, and pH. The test were carried out utilizing spectrophotometry to quantify the rates of reactions using absorbance and then converting using Beer’s law. The data was collected and plotted and showed that for substrate concentration there is a limit as to how much substrate can be utilized by an enzyme at a given time. The temperature plot shows that there is an ideal range for the enzyme to work most effectively without denaturing. The pH plot even more so than temperature showed that there is a cut off for pH the enzyme can work at. Introduction Enzyme Kinetics is the study of the chemical reactions that are catalyzed by enzymes. Enzymes are proteins or molecules that alter other molecules. They are catalysts, as in they alter other molecules and their reaction rates, but do not alter themselves and can be reused. The effected molecules are known as substrates. These substrates bind to the active site of the enzyme and are turned into products through processes known as enzymatic mechanisms. Enzymes serve many functions and are involved in many processes. The basic enzymatic mechanism equation is as follows. E + S ES ES* EP E + P In this equation, the E is defined as the enzyme, the S is the substrate, and the P is the product. It shows that there enzyme binds the substrate creating a enzyme substrate complex which is a transition state for the substrate to then become the product and be released. 2
In this experiment we utilized Michaelis-Menten kinetics to describe the rate at which a reaction occurred. Enzymatic reaction rates do not show a linear response if the substrate is increased so the process of measuring the initial rate (V0) over a variety of different substrate concentrations (denoted as [S]) is used. The reaction rate increases as [S] increases until the enzyme is saturated with substrate. When this happens the rate of the reaction plateaus. This point is referred to as Vmax and is the enzymes maximum rate. The Michaelis-Menten constant, KM, is defined as the substrate concentration where V0is equal to 1/2 Vmax. KMis used to quantify an enzymes ability to catalyze reactions. The lower the KM, the better the enzyme is at creating product with small amounts of substrate. The Michaelis-Menten equation is as follows. V0= (Vmax[S])/(KM + [S]) In this experiment we looked at the rate of the reaction for the enzyme alcohol dehydrogenase (ADH) which was isolated from yeast. This enzyme catalyzes the oxidation of ethanol and produces acetaldehyde. The reaction is as follows Ethanol + NAD+ acetaldehyde + NADH + H+ Ethanol is the substrate, Nicotinamide adenine dinucleotide (NAD) is the oxidized coenzyme,

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture