Mechanism of Enzyme Action PDF

MECHANISM OF ENZYME ACTION By: Dr. Sara Assem Lecturer of Medical Biochemistry and Molecular Biology DEAR STUDENTS &  TRANSFER GOAL Understand how enzymes catalyse the reactions and how they are classified according to their action. ...

MECHANISM OF ENZYME ACTION By: Dr. Sara Assem Lecturer of Medical Biochemistry and Molecular Biology DEAR STUDENTS &  TRANSFER GOAL Understand how enzymes catalyse the reactions and how they are classified according to their action.  STUDENTS’ LEARNING OUTCOMES(SLOs) At the end of this session, the student will be able to: 1. Describe how enzymes work as catalysts 2. Apply the action of enzymes on varied biological processes 3. Classify enzyme families according to their action on different bonds. 4. Predict and appraise the clinical impact of pharmacological activation Antibodies  The transition state is the top of the energy barrier Transition separating the State reactants and An unstable products. state in with high probability of making or breaking a chemical bond to form the product. Antibodies  Transition State Rate of a reaction varies directly with the number of substrate molecules in the transition state Antibodies  Energ Energy of The y Activation amount of energy required to bring 1 gram of substrate to the transition state. Antibodies  What do you think would be the effect of Enzymes on “Energy of Activation”? Antibodies  Enzyme provides an alternative pathway for the reaction with a lower What do you Ea. think would be The Lower the Energy the effect of of Activation Enzymes on The more substrate “Energy of molecules enter the Transition State Activation”? The faster the Antibodies  Transition Energy of State Activation Energy Barrier Antibodies  1- OXIDO-REDUCTASES Catalyze the oxidation reduction Coenzyme reactions (Removal of Lactate hydrogen Dehydrogenase or electrons from  1- OXIDO-REDUCTASES Catalyze the oxidation reduction Substra te reactions Hydroge (Removal of n Enzym hydrogen or e electrons from substrate)  2- TRANSFERASES Catalyze the transfer of H20 C, N or P containing TH CH2- F THF groups from Serine hydroxy substrate methyl transferase 10/17/2024  2- TRANSFERASES Catalyze the transfer of C, N or P containing groups from substrate Substrat e 10/17/2024  3- HYDROLASES Catalyze the cleavage O of bonds by H H H2 adding 0 2 NH3 water Urea CO2 Urease 10/17/2024  3- HYDROLASES Catalyze the cleavage of bonds by Bonds in substrat Enzyme adding es water 10/17/2024  4- LYASES Catalyze CO2 the cleavage of C-C, C-S, C-N Pyruvate Decarboxylase 10/17/2024  4- LYASES C-C Catalyze C-S the C-N Substra cleavage of te C-C, C-S, C- Enzyme N 10/17/2024  5- ISOMERASES Catalyze the re- arrangeme nt of isomers Methyl malonyl CoA mutase 10/17/2024  5- ISOMERASES Catalyze Substra the re- te Enzyme arrangeme nt of isomers 10/17/2024  Catalyze 6- LIGASES the formation of bonds between C & 0,S,N coupled with e Pyruvate hydrolysis Carboxylase of high energy P 10/17/2024  Catalyze 6- LIGASES the formation of bonds between C & 0,S,N Enzym coupled e with e hydrolysis Bonds of high between C,O,N,S energy P 10/17/2024  Clinical Implications  1- Enzyme activation Tissue plasminogen activators, as alteplase, are drugs that activate plasmin (that degrades fibrin in used for emergency lysis of a the formed blood clot). blood clot in case of acute myocardial infarction Antibodies  More 2- Enzyme Commo n inhibition Non-steroidal anti- inflammatory drugs, as ibuprofen, inhibit the cyclooxygenase enzyme (COX), responsible for the formation of mediators of Therefore, they are used as pain, fever and analgesic, antipyretic and inflammation. anti-inflammatory. Antibodies  More 2- Enzyme Commo n inhibition Anticholinesterases, as pyridostigmine, are drugs that inhibit the cholinesterase enzyme [which breaks down Used for the treatment of acetylcholine ] ”Myasthenia Gravis” Acetylcholine is an important muscle weakness due to a neurotransmitter defect at neuromuscular Antibodies junction  If from the textbook. Add the chapter and pages Lecture notes Portal resources.......  TAKE-HOME MESSAGE Enzymes lowers the energy barrier, the activation energy and facilitate the entry of substrates to the transition state. We have 6 main classes of enzymes with different actions. Clinically some drugs perform their function by activation or inhibition of certain enzymes.  DEAR STUDENT: Don’t forget to complete your KWL chart And reflect on your learning experience by writing down what do you learnt from the lecture (3 points at least)