Biomedical Importance of Enzymes Basic concepts about Enzymes Classification of Enzymes as per IUB

Introduction Enzymes are biologic polymers that catalyze the chemical reactions. In their chemical nature all known enzymes are protein. They are high molecular weight compounds. Enzymes can be denatured and precipitated with salts, solvents and other reagents. Many enzymes may require the presence of other compounds-cofactors.

Apoenzyme & Holoenzyme

Enzymes catalyzes the chemical reactions. Participate in the breakdown of nutrients tom supply energy & chemical building blocks. Responsible to assemble building blocks into proteins, DNA, membranes, cell and tissues. Diagnosis and prediction of prognosis of many disease can be done by the presence and activity of many enzymes. Biomedical Importance of Enzymes

Some of the earliest studies were performed in 1835 by the Swedish chemist Jon Jakob Berzelius who termed their chemical action catalytic. In 1926, however, that the first enzyme was obtained in pure form, by James B. Sumner of Cornell University. Sumner was able to isolate and crystallize the enzyme urease from the jack bean. Earlier studies about Enzyme

Enzymes are extremely selective. Enzymes are specific not simply for the type of reaction but also for a single substrate or a set of closely related substrate. Enzymes are stereospecific catalysts. In general there are four distinct types of specificity: -Absolute specificity -Group specificity -Linkage specificity -Stereochemical specificity Enzyme and its Specificity

International Union of Biochemistry (IUB) developed an system of enzyme nomenclature in which each enzyme has a unique name and code number that identify the type of reaction catalyzed and the substrate involved. As per this system name starts with ‘EC’ followed by four digits- 1 st digit represent the class 2 nd digit represent the subclass 3 rd digit is sub-group 4 th digit give the number of particular enzyme in the list Naming &Classification of Enzymes

Enzymes are grouped into six classes: 1. Oxidoreductases 2. Transferases 3. Hydrolases 4. Lyases 5. Isomerases 6. Ligases Classification of Enzymes

Oxidoreductases: Catalyze oxidations and reductions Transferases: Catalyze transfer of moieties such as glycosyl, methyl, or phosphoryl groups. Hydrolyases: Catalyze hydrolytic cleavage of C-C, C-O, C-N, and other bonds. Lyases: Catalyze cleavage of C-C, C-O, C-N, and other bonds by atom elimination, leaving double bonds. Isomerases: Catalyze geometric or structural changes within a molecule. Ligases: Catalyze the joining together of two molecules coupled to the hydrolysis of ATP. Classification of Enzymes

The IUB name of hexokinase is ATP:D-hexose 6- phosphotransferase E.C This name identifies hexokinase as a member of class 2 (transferases). Second digit 7 indicates subclass (transfer of a phosphoryl group). Third digit 1 represents sub-subclass ( alcohol is the phosphoryl acceptor). “hexose-6” indicates that the alcohol phosphrylated is on carbon -6 of a hexose. Naming of Hexokinase

Structure & action of Hexokinase