Which term describes the portion of an enzyme where the substrate binds?

Which term describes the portion of an enzyme where the substrate binds?

• A. Substrate binding site
• B. Active site
• C. Catalytic site
• D. Enzyme pocket

Answer: (B)

Enzymes have a region where the substrate binds that is called the active site. This pocket or groove is formed by a precise arrangement of amino acids whose shapes and chemical properties fit the substrate so it can sit in place. When the substrate binds, the active site holds it in the correct orientation and often changes shape slightly to better accommodate the reaction—this is the induced-fit idea. This tight, specific binding and the environment inside the active site help stabilize the transition state and provide the chemical conditions needed for catalysis, effectively lowering the energy barrier to reaction. After the reaction occurs, the products depart from the active site, and the enzyme is free to catalyze more substrate molecules. Other terms like catalytic site or substrate binding site are less standard for naming the region as a whole; the active site is the most precise and widely used term.

Enzymes have a region where the substrate binds that is called the active site. This pocket or groove is formed by a precise arrangement of amino acids whose shapes and chemical properties fit the substrate so it can sit in place. When the substrate binds, the active site holds it in the correct orientation and often changes shape slightly to better accommodate the reaction—this is the induced-fit idea. This tight, specific binding and the environment inside the active site help stabilize the transition state and provide the chemical conditions needed for catalysis, effectively lowering the energy barrier to reaction. After the reaction occurs, the products depart from the active site, and the enzyme is free to catalyze more substrate molecules. Other terms like catalytic site or substrate binding site are less standard for naming the region as a whole; the active site is the most precise and widely used term.