MODULE-2-ENZYMOLOGY-PART-1 (1).pdf

CLINICAL CHEMISTRY 2 which reacts with a reagent to generate a product. ENZYMOLOGY PART 1 Mo...

CLINICAL CHEMISTRY 2 which reacts with a reagent to generate a product. ENZYMOLOGY PART 1 Molecules where enzyme I. Introduction catalyzes a reaction. Enzymes are specific biologic These are the components proteins that catalyze consumed in the reaction. biochemical reactions without altering the equilibrium point of IV. Enzyme Structure the reaction or being consumed or changed in composition. The other substances in the reaction are converted to products. The catalyzed reactions are frequently specific and essential to physiologic functions, such as the hydration of carbon dioxide, nerve conduction, muscle contraction, nutrient degradation, and energy use. II. Enzyme Found in all body tissue, but enzymes frequently appear in the serum following cellular injury or, sometimes, in smaller amounts, from degraded cells. Lowers the activation energy (energy required before the reaction takes place) of a i. ACTIVE SITE chemical reaction. It is the region of an Acts as facilitators of chemical enzyme where reactions. substrate molecules Present in low concentrations in bind and undergo a the blood. chemical reaction Serves as biological markers for Consists of amino acid specific organs with injury. residues that form III. Substrate temporary bonds with A reactant in a chemical reaction the substrate (binding is called a substrate when acted site). upon by an enzyme. It is typically Also consists of residues the chemical species being that catalyze a reaction observed in a chemical reaction, of the substrate (catalytic site). PALADA, TJG  CLINICAL CHEMISTRY 2 ii. ALLOSTERIC SITE Referred to as a cavity other than the active site may bind regulator molecules and, thereby, be significant to the basic enzyme structure. It allows molecules to either activate or inhibit, or turn off, enzyme activity. iii. ISOENZYMES group of enzymes with different form and efficiencies but catalyzes similar reactions. iv. COFACTORS nonprotein molecule attached to an enzyme, v. HOLOENZYME completing its active It is a catalytically active site enzyme consisting of an Cofactors can either be apoenzyme combined ions, such as zinc and with its cofactor. iron ions, or organic Examples of molecules, such as holoenzymes include vitamins or vitamin- DNA polymerase and derived molecules. RNA polymerase which It assists in enzyme contain multiple protein activity. subunits. Can substitute It is also referred as a substrates. complete and active Additional catalyzing system. requirements for certain enzyme activations. inorganic cofactors are called and classified as "Activators". Organic cofactors are referred to as “Coenzymes”. PALADA, TJG  CLINICAL CHEMISTRY 2 (isoenzymes), which alters rates and specificity suitable for vi. PROENZYME (ZYMOGEN) selective cellular homeostasis. Also known as the Controlled by the binding of "inactive form of an small molecules that cause Enzyme”. conformational change in the Identified as substances enzyme’s structure. which is metabolized Enzymes do not affect the value into an enzyme. of equilibrium constant between reactants and the product. V. Enzyme Specificity Enzyme specificity is essential to VII. Enzyme-Substrate(ES) function, not only to maintain Complex the faithful reproduction of The enzyme substrate complex metabolic pathways but also to is a temporary molecule formed prevent unwanted side when an enzyme comes into reactions at a particular active perfect contact with its site. substrate. An adduct (product of an addition reaction) is formed by THE THREE (3) CLASSIFICATIONS OF ENZYME the physical adsorption of the SPECIFICITY substrate to the active site. Binding Specificity - refers to the interaction where an enzyme 2 ENZYME-SUBSTRATE MODELS reacts to a specific substrate or a Lock-and-key Model substrate with a similar ▪ The lock and key model composition. also called Fisher's Reaction Specificity - refers to theory is one of two the interaction where an models which describe enzyme catalyzes a unique the enzyme-substrate chemical reaction, with no interaction. The lock and minor byproduct key model assumes that formed(absolute). the active site of the Stereoselective - refers to the enzyme and the interaction where an enzyme substrate equal shaped. recognizes only one enantiomeric form of the substrate. VI. Enzyme activity Different tissues contain isoforms of the same enzymes PALADA, TJG  CLINICAL CHEMISTRY 2 Induced Fit Model enzyme called lactic acid ▪ It describes that only the dehydrogenase. proper substrate is capable of inducing the proper alignment of the Each enzyme has an EC numerical code – active site that will 4 digits separated by decimal points. enable the enzyme to ▪ First digit refers to the class of perform its catalytic the enzyme. function. ▪ Second and third digits refers to the subclass and sub subclass of the enzyme. ▪ Final number is the serial number specific to the enzyme. ▪ In addition to naming enzymes, the IUB system identifies each enzyme by an EC numerical code containing four digits separated by decimal points. The first digit places the enzyme in one of the VIII. Classification and following six classes: nomenclature To standardize enzyme nomenclature, Enzyme Commission (EC) of International Union of Biochemistry (IUB) assigns a systematic name to each enzyme, defining the substrate acted on, the reaction catalyzed, and, possibly, the name of any coenzyme involved in the IX. REFERENCES reaction. Bishop, M., et. al. (2013). Clinical chemistry: Enzymes are named according principles, techniques, and correlations 7th to the substrate being catalyzed edition. Philadelphia followed by the suffix -ase or also includes the type of Lippincott Williams & Wilkins McPherson, RA., reaction catalyzed sometimes. Pincus, MR. (2022)Henry's Clinical Diagnosis and Examples: Management by Laboratory Methods 24th ▪ RNA is hydrolyzed by an edition. Philadelphia: Elsevier Inc. enzyme called ribonuclease. ▪ Lactic acid is oxidized to pyruvic acid by an PALADA, TJG  CLINICAL CHEMISTRY 2 PALADA, TJG