Question

Made for each other. Match the term with the proper description. (a) Enzyme________ (b) Substrate________ (c) Cofactor________ (d) Apoenzyme________ (e) Holoenzyme________ (f) Coenzymes________ (g)\(\Delta G^{0}\)________ (h) Transition state________ (i) Active site________ (j) Induced fit________ 1\. The least-stable reaction intermediate 2\. Site on the enzyme where catalysis takes place 3\. Enzyme minus its cofactor 4\. Protein catalyst 5\. Function of \(K_{\mathrm{eq}}^{\prime}\) 6\. Change in enzyme structure 7\. Reactant in an enzyme-catalyzed reaction 8\. A coenzyme or metal 9\. Enzyme plus cofactor 10\. Small vitamin-derived organic cofactors

Short answer

(a) 4, (b) 7, (c) 8, (d) 3, (e) 9, (f) 10, (g) 5, (h) 1, (i) 2, (j) 6.

Step-by-step solution

Match Enzyme

(a) The term 'Enzyme' is defined as a 'Protein catalyst', which matches with description 4.

Match Substrate

(b) The term 'Substrate' is defined as a 'Reactant in an enzyme-catalyzed reaction', which matches with description 7.

Match Cofactor

(c) The term 'Cofactor' is defined as a 'Coenzyme or metal', which matches with description 8.

Match Apoenzyme

(d) The term 'Apoenzyme' is defined as an 'Enzyme minus its cofactor', which matches with description 3.

Match Holoenzyme

(e) The term 'Holoenzyme' is defined as 'Enzyme plus cofactor', which matches with description 9.

Match Coenzymes

(f) The term 'Coenzymes' is defined as 'Small vitamin-derived organic cofactors', which matches with description 10.

Match Standard Free Energy Change

(g) The term '\(\Delta G^{0}\)' is related to the 'Function of \(K_{\mathrm{eq}}^{\prime}\)', which matches with description 5.

Match Transition State

(h) The term 'Transition state' is defined as 'The least-stable reaction intermediate', which matches with description 1.

Match Active Site

(i) The term 'Active site' is defined as 'Site on the enzyme where catalysis takes place', which matches with description 2.

Match Induced Fit

(j) The term 'Induced fit' is defined as 'Change in enzyme structure', which matches with description 6.

Key concepts

Enzyme-Substrate Interaction

Enzyme-substrate interactions are essential to understand how enzymes function. An enzyme acts like a key, and the substrate is the lock. When the enzyme and substrate come together, they form an enzyme-substrate complex. This complex is necessary for the enzyme to perform its function, which is usually to speed up a chemical reaction.
When a substrate binds to an enzyme, it usually does so at a very specific location on the enzyme, known as the active site. This specificity is due to the unique shape and chemical environment of the active site, which complements the substrate.
The concept of 'induced fit' describes the slight alteration in the enzyme's structure upon substrate binding, enhancing the interaction. This adjustment allows the enzyme to bind the substrate more tightly and efficiently. This interaction is crucial for lowering the activation energy of the reaction, enabling it to proceed faster and more efficiently than it would without the enzyme's presence.
Enzyme-substrate interactions demonstrate the elegance of biochemical processes, showing the precision required for metabolic reactions to occur within living organisms.

Cofactors and Coenzymes

Enzymes need a bit of help to perform optimally, and this is where cofactors and coenzymes come into play. Each enzyme may require additional molecules or ions to be active, known as cofactors. Cofactors can be metallic ions or organic molecules.
Most of the time, we encounter these cofactors in two forms: simple metal ions or complex organic molecules known as coenzymes. Coenzymes are often derived from vitamins, indicating the importance of adequate vitamin intake in our diets to support a healthy metabolism.
Think of cofactors as enzyme assistants, indispensable for many enzymatic activities. They assist in transforming substrates into products more efficiently. It is interesting to note that without these cofactors, some enzymes are inactive or less efficient in catalyzing reactions. The enzymes that do not include their cofactors are known as apoenzymes. Once the cofactor binds to complete the active form of the enzyme, it is known as a holoenzyme.
This highlights the vital role cofactors and coenzymes play in ensuring enzymes function correctly, which is central to many biological processes in living organisms.

Active Site and Catalysis

The active site of an enzyme is a finely-tuned environment, perfectly structured to catalyze chemical reactions. It is the location on the enzyme where the substrate attaches and undergoes its transformation into product(s).
This part of the enzyme doesn’t just fit the substrate; it may also help in breaking bonds and forming new ones, fundamentally altering the substrate's chemical structure. This transformation is called catalysis, a process where the activation energy of a reaction is lowered, thus speeding up the reaction without the enzyme undergoing any permanent change.
The shape and chemical properties of the active site must be incredibly specific to interact with its substrate, highlighting the precision required in enzyme function. Sometimes, the active site can create a microenvironment that is either more acidic or basic than the surrounding solution, which aids the catalysis process.
Understanding the role of the active site is essential in fields such as drug design. Inhibitors often target the active site to block the enzyme's activity, providing therapeutic effects against diseases. This illustrates just how vital the relationship between the active site and catalysis is in both natural and medical sciences.