Enzymes and Co-Enzymes Biochemistry PDF

Enzymes and Co-Enzymes Dr. Majed A. K. Al-Mansoub MDP 10108 Department of Basic Medical Sciences Foundation, Year 1 Biochemistry FMHS, UNIMAS Lecture Content 1. What are enzymes and makes them special? 2. Classification of enzymes 3. Wh...

Enzymes and Co-Enzymes Dr. Majed A. K. Al-Mansoub MDP 10108 Department of Basic Medical Sciences Foundation, Year 1 Biochemistry FMHS, UNIMAS Lecture Content 1. What are enzymes and makes them special? 2. Classification of enzymes 3. What affects enzyme activity? 4. Control of enzyme activities 5. Enzymes as diagnostic markers By the end of this lecture you should be able to: Discuss the concept of biological catalysts Discuss the IUB classification of enzymes & how to name them Explain the concept of co-enzymes Explain basic properties od enzymes like specificity, catalytic activity and active site Discuss the concept of enzymes used in medical diagnostics Explain factors that affect enzyme activity like temperature, pH, enzyme and substrate concentration, inhibitors Discuss control of enzyme activity Explain feedback inhibition ◦ The reaction represented by this graph is a combustion reaction involving the reactants glucose (C6H12O6) and oxygen (O2). ◦ The products of the reaction are carbon dioxide (CO2) and water (H2O). Energy ◦ Energy is also released during the reaction. ◦ The enzyme speeds up the reaction by lowering the activation energy needed for the reaction to start. ◦ With the enzyme, the activation energy is much lower, and so the reaction can occur at a faster rate. Progress of the reaction Not to forget enzymes have a wide range of applications in the industry Maltase has bond specificity, targeting only the glycosidic bond in maltose, not absolute or group specificity. That means the enzyme acts on a particular type of bond, such as the α-1,4 glycosidic bond in maltose Classification of Enzymes These are the six International Union of Biochemists (IUB) classes of enzymes and the reactions they catalyze.  Enzyme Class Reaction Catalyzed Some Examples Reactions Examples in Metabolism Dehydrogenases catalyse reactions catalyze the redox (reduction & Oxidoreductases oxidation) reaction. in which a substrate is oxidised or reduced. catalyze transfer a functional groups Transaminases which catalyze the such as methyl or glycosyl from a transfer of amino group or kinases Transferases donor molecule to an acceptor which catalyze the transfer of molecule. phosphate groups. Lipases catalyze the hydrolysis of lipids, catalyze the hydrolytic cleavage of and proteases catalyze the hydrolysis of Hydrolases C-C, C-O, C-N, P-O, and certain proteins. other bonds, including acid Pyrophosphatases breakdown of anhydride bonds. pyrophosphate into inorganic phosphate. catalyze cleavage of C-C, C-O, C-N, and other bonds by elimination, leaving Decarboxylases catalyze the Lyases double bonds, and also add groups to removal of carboxyl groups. double bonds. Isomerases may catalyze the Isomerases conversion of an aldose to a ketose, catalyze geometric or structural and mutases transfer functional changes within a single molecule. group from one atom to another within a substrate. catalyze the joining together of two molecules, coupled to the hydrolysis of Synthetases link two smaller Ligases a pyrophosphoryl group in ATP or a molecules to form a larger one. similar nucleoside triphosphate. The enzyme’s name is comprised of the names of the substrate(s), the product(s) and the enzyme’s functional class. Enzymes of diagnostic interest are enzymes which are normally not found in the plasma. Thank You Acknowledgement to Prof. Dr. Gabriele R. A. Frömming