How are enzymes commonly regulated?

Enzymes are commonly regulated via covalent modifications. This process involves the addition or removal of functional groups (such as phosphate groups in phosphorylation) or other molecules (like acetyl or methyl groups), which can dramatically alter the enzyme's activity, structure, or stability. This type of regulation is significant because it allows for rapid control over an enzyme's functionality, often in response to intracellular signaling.

Covalent modifications can either activate or deactivate an enzyme, providing a mechanism for fine-tuning metabolic pathways quickly in response to varying cellular conditions. For instance, phosphorylation can result in a conformational change that either enhances or inhibits the enzyme's activity.

Other mechanisms of enzyme regulation exist, such as temperature changes, alterations in pH, and variations in substrate concentration. However, these mechanisms generally influence enzyme activity indirectly rather than through direct, regulated modification of the enzyme's structure or function as seen with covalent modifications.