ENZYMES

1 EJC H2 Biology T1W10 Enzymes Biomolecules of Life (Part 2) - Enzymes 1. Overview of Topic Many enzymes are made up of proteins. Enzymes are biological catalysts which speed up the rate of reactions. In this topic, we will examine the mode of action of enzymes in terms of their catalytic action via their activity sites. We will also study how en zyme-substrate complexes are formed through the proposed models of enzyme substrate interactions. Various factors such as temperature, pH, enzyme concentrations & substrate concentrations affect enzyme catalysed reactions. Enzyme can also be influenced by inhibitors and activators which can regulate the rates of enzymatic reactions. 2. Learning Outcomes a. Explain the mode of action of enzymes in terms of an active site, enzyme -substrate complex, lowering of activation energy and enzyme specificity using the l ock-and-key and induced -fit hypothesis. b. Investigate and explain the effects of temperature, pH, enzyme concentra tion and substrate concentration of an enzyme-catalysed reaction by measuring rates of formation of products (eg measuring gas produced using c atalase) or rate of disappearance of sub strate (e.g. using amylase, starch and iodine). c. Describe the structure of competitive and non-competitive inhibitors with reference to the binding sites of the inhibitor. d. Explain the effects of competitive and non-competitive inhibitors (including allosteric inhibitors) on the rate of enzyme activity. 3. References Campbell, N.A. and Reece, J.B. (2011), Biology (9th edition), Pearson Benjamin-Cummings, San Francisco Brooker, R.J., Widmaier, E.P., Graham, L. and Stiling, P. (2008), Biology, Mc-Graw-Hill, New York

2 EJC H2 Biology T1W10 Enzymes Contents 1. Overview of Topic ...................................................................................................... 1 2. Learning Outcomes.................................................................................................... 1 3. References ................................................................................................................. 1 4. Introduction ............................................................................................................... 3 5. General Information on Enzymes .............................................................................. 4 A. Definition ............................................................................................................... 4 B. General Characteristics of Enzymes ...................................................................... 4 6. The Active Site of Enzymes ........................................................................................ 6 7. Enzyme co-factors ..................................................................................................... 9 8. Models of Enzyme Action .........................................................