BISC 220Lg Lecture Notes - Lecture 10: Enzyme Catalysis, Covalent Bond, Sucrase
6 Apr 2017
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Document Summary
Although enzymes are proteins, some have molecules that participate in catalysis. Rna polymerase: catalyzes formation of rna but not dna. Hexokinase: accelerates the phosphorylation of a hexose monosaccharide (eg. glucose) In animals, sucrase catalyzes reaction of hydrolysis to breakdown into glucose and fructose. Substrates held in active site by weak interactions. The r groups (side chains) of an enzyme"s amino acids may directly participate in making substrates more chemically reactive. Acidic or basic side chains of amino acids form the active site and transfer h+ to or from the substrate, destabilizing a covalent bond in a substrate. Functional group side chain forms a temporary covalent bond with substrate. Some have metal ion cofactors, which involve the gain or loss of electrons, called redox reactions. Normal binding: substrate to active site of enzyme. Competitive inhibition: blocks active site of enzyme. Noncompetitive inhibition: blocks other part of enzyme to change shape and not allow the substrate to bond.
