PPT-ALLOSTERIC ENZYMES REGULATION

By Shubhani singh thakur department of biochemistry Contents Introduction History Properties Modulators Types of Allosteric Regulation Models of Allosteric Regulation Allosteric. C483 Spring 2013. Questions. 1. Which . statement is false about allosteric regulation? . A) It is usually the mode of regulation for the last step in reaction pathways since this step produces the final product. . Lesson . 2. – The Catalytic Cycle. What do enzymes do?. Enzymes lower the . activation energy . E. a. . required for a reaction to occur.. Catalytic Cycle of . Sucrase. Enzyme Substrate Complex. Lock and Key Model. Definition of an enzyme. Enzyme. is . protein . . catalyst. (i.e. . increase the rate of reactions. ). . NOT. changed during the reaction. A catalyst is a chemical agent that speeds up a reaction without being consumed by the reaction. An enzyme is a catalytic protein. Hydrolysis of sucrose by the enzyme sucrase is an example of an enzyme-catalyzed reaction. 1. Dr. Nikhat Siddiqi. The most responsive regulation of amino acid . synthesis takes . place through feedback inhibition of the first . reaction in . a sequence by the end product of the pathway.. This first reaction is usually irreversible and . Phosphorylation is a type of covalent modification that activates or deactivates an enzyme.. a. ) A . kinase activates an . inactive enzyme . by phosphorylation. . b. ) A . phosphatase activates . an inactive . The living cell is a miniature chemical factory where thousands of reactions . occur. The cell extracts energy and applies energy to perform . work. Some organisms even convert energy to light, as in bioluminescence. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings. Enzymes. 3. 4. The . Control of Metabolism. 1.. . Metabolic control often depends on . allosteric. regulation . التحكم الجانب. 8.1 Isozymes. Isozymes . are enzymes that differ in amino acid sequence but catalyze the same chemical reaction.. Example: Cyclooxygenase Enzymes (Cox1 and Cox2). Example: Cyclooxygenase Enzymes (Cox1 and Cox2). 2- ISOENZYMES:. Some . of the enzymes are present in more than one form having the same molecular weight and differ in conformational structures called isoenzymes, e.g. Trypsinogen isoenzymes . are present . Allostery. :. Glycogen Phosphorylase:. Control by . Allostery. & Phosphorylation. Glycogen. (n). +. P. i. +. Glycogen. (n-1). . (more active). Enzyme Regulation. Control by . Allostery. :. Glycogen Phosphorylase:. Flow of energy . Energy is the ability to do work or bring a change. . There are 2 types of energy. Kinetic- Energy of motion. Potential- Stored energy . Laws of Thermodynamics. There is a constant flow of energy in biological systems. . Drill:. . What background knowledge do you have on enzymes?. Enzyme Structure and Function. Enzymes are . protein catalysts. They speed up the rate at which reactions occur. Lower the activation energy by creating a microenvironment that is energetically more favorable for a reaction. Metabolic Control Mechanisms . Anadozie, S.O Ph.D.. Metabolic Control Mechanisms . The metabolic pathways are complex and interdependent. With the changing . environments, . the reactions of metabolism must be finely regulated to maintain a constant set of conditions within cells, a condition called homeostasis..