BIOC312 Lecture Notes - Lecture 9: Epimerase And Racemase, Stereospecificity, Binding Energy
28 Jul 2016
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Document Summary
Enzymes are proteins with a 3d structure which provides an active site for; Binding of substrates and catalytic conversion to products. Enzymes may be single proteins or may contain 2 or more subunits. Catalysts speed up attainment of reaction but do not effect the equilibrium itself and enzyme remains unchaged. Enzymatic reactions- 103 and 1017 faster than corresponding uncatalysed reactions. Stereospecificity- enzymes usually act upon only one stereoisomer of a substratereaction specificity-enzyme product yields are essentially 100% (no formation of wasteful by- products) Six classes of enzymes; oxidoreductases, transferases, hydrolases, lyases, Catalyse transfer of chemical groups (movement of groups between substrates) Cleave a bond e. g. c-c, c-o, c-n, phosphoanhydride with addition of water to products. Catalyse lysis of a substrate by cleaving of c-c, c-o, c-n or other bond, leaving a double bond. For some lyases the reverse (addition to a double bond) is more important- synthase.
