Enzymes in Metabolic Pathways

Enzymes in Metabolic Pathways

• Enzymes are proteins that speed up metabolic chemical reactions, allowing cells to stay alive and function properly.
• Enzymes lower the energy needed for a reaction to start, making the reaction faster.

Enzyme-Substrate Binding

• Enzymes bind to substrates by changing their shape to fit the substrates better and stabilize them during the reaction.

Regulation of Enzymes

• Allosteric regulation: molecules bind to a different site on the enzyme, changing its activity (e.g., ATP inhibits PFK-1 in glycolysis).
• Covalent modification: adding or removing groups like phosphate activates or deactivates enzymes.
• Proteolytic cleavage: enzymes are activated by cutting (e.g., trypsinogen is cut to form active trypsin).
• Feedback inhibition: end products inhibit earlier steps in the pathways (e.g., isoleucine inhibits threonine deaminase).
• Compartmentalization: enzymes are kept in specific cell areas (e.g., fatty acid synthesis occurs in the cytoplasm, while breakdown occurs in mitochondria).

Importance of Enzymes

• Enzymes help maintain balance in the cell by controlling metabolic reactions and responding to changes.
• Enzymes regulate blood sugar levels (e.g., insulin and glucagon regulate enzymes that control blood sugar levels).
• The role of enzymes is crucial for speeding up and regulating metabolic reactions, ensuring cells function properly and stay balanced.

Learn about the role of enzymes in metabolic pathways, including how they speed up chemical reactions and are controlled by various mechanisms such as allosteric regulation. Discover how enzymes bind to substrates and stabilize them during reactions.