LIGAND‐ENZYME INTERACTIONS AND ENZYME REGULATION *

One of the basic problems in biochemistry is how enzymes are regulated to provide control of metabolism. Two of the processes of switching an enzyme “on” and “off’ involve the binding of regulatory ligands and chemical modifications of the enzyme. Most of the regulatory enzymes studied so far have been found to have several subunits. The interaction between these subunits is assumed responsible for the observed cooperativity of the binding of regulatory ligands. Often the initial signal for the enzyme activation is small and is amplified by having a cascade of enzymes each one of which activates the next. A good example of this is the system of enzymes which regulate the breakdown of glycogen.

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