CELL BIOLOGY
13 NOVEMBER 2007
Enzymes are biological catalysts. They are proteins that speed up reactions with low concentrations. These enzyme proteins are made up of linkages of amino acids. The links coil, and coil again forming a tertiary structure. This structure has a groove in it called an active site. The active site is where the substrates and reactants bind to catalyze a reaction. The bonds that bind the substrate to the active site are hydrogen bonds and ionic bonds. There are two different ways in which a substrate can bind to an active site. The first way is through the lock and key model. Certain substrates can bind only to certain active sites in the lock and key model. This is called the lock and key model because the active site is like the lock and the key is the substrate. Only certain keys can open certain locks. This accounts for the specificity; not all substrates can fit into all active sites. Another way in which substrates bind to active sites is called the induced fit model. This is where an active site changes its form to accommodate for certain substrates. There are several different biological factors that effect enzyme activity. Some of them include temperature, pH, and enzyme concentration. This experiment will be testing how much of an effect different concentrations of enzyme solutions have on reaction rates. There are many different kinds of enzymes. A group of people have formed the Enzyme Commission for organizing and identifying enzymes. They set up a system where each enzyme has a four number name. The enzyme for this reaction is malate dehydrogenase (MDH). Its enzyme commission number is 1.1.1.37. The first number is in reference to its class. In the case of MDH, it is a oxidoreductase meaning that it carries out oxidation-reduction
Cited: Becker, W, Kleinsmith, L, & Hardin, J (2006). The World of the Cell. San Francisco: Bemjamin Cummings. (Becker, Kleinsmith, and Hardin, 2006)