Examining Some Properties of the Enzymatic Reaction

Essay by lovely2000College, UndergraduateB, December 2002

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Introduction: In this experiment a deeper meaning in the catalysts of reactions is studied. Catalysts accelerate chemical reactions without permanently changing the reaction. Enzymes, catalysts in biochemical reactions, are globular proteins which lower the activation energy needed to begin a reaction and therefore increase the rate at which efficient reactions can occur. Proteins (henceforth enzymes) are complex molecules made of amino acids in polypeptide chains held together by peptide bonds. The structure of proteins is broken up into primary, secondary, tertiary, and quaternary structures which create complex structures which can be separated and identified by paper chromatography, or more importantly spectrophotometry can determine the concentration of proteins in an aqueous solution. Spectrophotometry is a quantitative analysis used to determine the amount or concentration of a substance ( -amylase) from its ability to absorb radiant energy. The substance is usually colored and radiant energy used is visible light, which passes through the solution and is either absorbed or transmitted.

The spectrophotometer measures is an instrument (used here in our experiment) which electronically measures the amount of transmitted and absorbed light, and can determine concentration and wavelength. The concentration of a solution can be determined because the amount of light absorbed by a solution is dependent on its concentration. A relationship between absorbance and concentration can be made by the Beer-Lambert Law which states absorbance is equal to a molar extinction coefficient times the concentration of the solution times the length of the light path through the solution. The absorbances over a range of known concentrations of the substance are measured at lambda max, the wavelength which shows maximal absorbency. For the purpose of our lab, wavelength will not need to be found, but merely the spectrophotometer must be set to 560 nm. The reacting molecule in an enzymatic reaction is called...