Enzyme Lab Acid Phosphatase for C335 Biochemistry_1

Enzyme Lab Acid Phosphatase for C335 Biochemistry_1 - 1...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 Experiment Enzyme Kinetics THEORY Enzymes In General Enzymes are proteins which act as biological catalysts. They allow reactions in the cell to proceed at appreciable rates under normal physiological conditions. As is true of other catalysts, enzymes speed up the rate at which a reaction reaches equilibrium by lowering the energy of activation for the catalyzed reaction. However, they do not affect the position of equilibrium for the reaction. In order for an enzyme to catalyze the conversion of a substrate (reactant) to product, the substrate must first bind to the enzyme at a specific site called the active site to form an E-S complex (Michaelis-Menton complex). The E-S complex is then converted to product. For enzyme-catalyzed reactions involving a single substrate, the following equation applies: E + S ---> E -S -----> E + P (I) <— where E = enzyme S = substrate E-S = enzyme-substrate complex or Michaelis-Menton Complex P = product Factors Affecting Enzyme Activity There are a number of factors which affect the rate (or initial velocity, v o ) of an enzyme- catalyzed reaction: (1) the concentration of the enzyme, (2) the concentration of the substrate, (3) temperature, (4) pH, (5) the presence of inhibitors, and (6) the presence of allosteric effectors (in the case of regulatory enzymes). From equation (I) it should be evident that the rate of an enzyme-catalyzed reaction is proportional to the concentration of the enzyme - i.e. as the enzyme concentration increases, the rate of the enzyme-catalyzed reaction increases. As one as continues to increase the concentration of the enzyme, the rate of the enzyme-catalyzed reaction will increase. See the figure on the following page. 2 If the enzyme concentration is held constant and the substrate concentration is increased, initially the rate of the enzyme catalyzed reaction will increase. However, as the substrate concentration is increased further, a point is reached at which the rate of the enzyme catalyzed reaction remains the same. This phenomenon is known as saturation and is due to the fact that at higher substrate concentrations all of the active sites of the enzyme are occupied. At this point, increasing the substrate concentration no longer increases the rate of the enzyme-catalyzed reaction because the excess substrate does not have any free active sites to bind to. As temperature increases, the rate of an enzyme-catalyzed reaction increases. However, at higher temperatures, denaturation of the enzyme will result in a decrease in the rate. 3 The temperature at which the maximum rate occurs is known as the optimum temperature. The rates of a majority of enzyme-catalyzed reactions exhibit a strong dependence on pH....
View Full Document

This note was uploaded on 12/10/2011 for the course BCH 5045 taught by Professor Guy during the Fall '08 term at University of Florida.

Page1 / 50

Enzyme Lab Acid Phosphatase for C335 Biochemistry_1 - 1...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online