Intro to Enzymes

Enzymes

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Biology I Lab

Wednesday’s 2-3:50pm

Introduction

An enzyme can be defined as a macromolecule that acts as a catalyst and is composed of proteins. They speed up chemical reactions by lowering the activation energy (Roberts, 2009). The action of enzymes can be affected by various factors. The environment an enzyme is required to work in has a major impact on the reaction. If the temperature increases, the enzyme will work faster. If it decreases, the enzyme will work at a slower pace. Another major factor that affects enzymes is pH, which can be defined as a measure of hydrogen ion concentration equal to -log [H+] and ranging in value from 0-14 (Reece, Urry, Cain, Wasserman, Minorsky, Jackson, 2011). A pH level lower than 7 indicates the solution is acidic, anything above 7 is a basic solution. If an enzymes pH is too high or too low, it will not function (Roberts, 2009). For example, the enzyme Pepsin requires an acidic pH level of about 2 to function. Lactase is an enzyme found in the small intestine and works best in a pH level of 7 to 8.5 (Roberts, 2009). The role of lactase is to act with lactose and liberate the monosaccharaides glucose and galactose. If the pH optimum for the lactase enzyme is not achieved or maintained, the enzyme will most likely not function (Roberts, 2009).

The purpose of this experiment was to determine which pH lactase will work best in. It was hypothesized that tube #4 with the lactase suspended in buffer pH = 7 would have the optimum pH for the lactase enzyme. The reason for this was because lactase is produced in the small intestine, and the small intestine has a standard pH range of 7-8.5. This experiment used five solutions, each with lactase suspended in buffer with pHs of 3, 5, 7, and 9, leaving one of the five test tubes used containing 1mL of DI water to act as the experiments negative control. The source of sugar for the experiment was...