Conformational change The enzyme switches back and forth between the two forms. They are in equilibrium. Inactive form Active form Figure 6.19 Allosteric Regulation of Enzymes

Conformational change Inactive form Active form Allosteric site Active site Figure 6.19 Allosteric Regulation of Enzymes

When the enzyme is in its inactive form, the allosteric sites on the regulatory subunits can accept inhibitor. Allosteric regulation Inactive form Catalytic subunit Regulatory subunit Figure 6.19 Allosteric Regulation of Enzymes

Allosteric regulation Catalytic subunit Regulatory subunit Inactive form Allosteric inhibitor Figure 6.19 Allosteric Regulation of Enzymes

When the enzyme is in its active form, the active sites on the catalytic subunits can accept substrate. Allosteric regulation Active form Figure 6.19 Allosteric Regulation of Enzymes

Once a site is filled with a substrate or inhibitor, binding at a second site of the same type is favored. Cooperativity Substrate Figure 6.19 Allosteric Regulation of Enzymes

Cooperativity No product formation Product formation Figure 6.19 Allosteric Regulation of Enzymes