Enzymes in Drug Discovery
In simplest terms, enzymes are protein catalysts employed by nature to facilitate the chemical transformations required to sustain life. Since the 20th century, thousands of enzymes have been identified as key mediators of a wide range of biological functions such as signal transduction, muscle contraction, cell size regulation, viral infection, and fluorescence. Inhibitors that take advantage of these chemical interactions are among the most potent and effective drugs known. As a leading company in the protein science area, Creative Biolabs has established mature platforms for enzymes research including mechanism discovery, inhibitor screening, and novel target development. We are glad to share our experience in enzymes studies.
Introduction of Enzymes
Structurally, enzymes are composed of a series of amino acids that folds and twists to form a specific three-dimensional shape based on various chemical interactions. However, the number of amino acids required for enzymatic activity is highly variable from 62 to over 2500 amino acid residues. Despite their complex structure, the active site is only a small portion of the full-length enzyme and the remainder of the enzyme is essentially scaffolding required to create the active site. Therefore, enzymes are highly specific in nature, typically catalyzing only a single reaction on a very narrow range of substrate due to the difference between active sites. Nowadays, six classes of enzymes were identified by functions.
Fig.1 Representative examples of six classes of enzymes. (Blass, 2015)
Mechanism of Enzymes
Fig.2 “Lock and key” model and
“induced fit” model. (Robinson, 2015)
Scientists have raised two models to explain how enzymes accelerate chemical reactions. The “lock and key” model proposed that enzymes and substrates must have complementary geometric shapes that exactly fit each other for an enzyme to function on a given molecule. While the “induced fit” model suggested that the binding of a substrate to the active site could induce conformational changes to the enzyme itself. Anyway, both models agreed that enzymes increased the reaction rate by forming the transition states and lowering the activation energy. Enzyme transition states engage the most optimal enzyme-ligand interactions, and extremely potent inhibitors can be designed from knowledge of transition state.
Introduction of Enzymes Inhibitors
Since discovered in the 20th century, enzymes are regarded as typical drug targets due to their high binding activity and important functions. As of April 2005, 317 FDA-approved drugs function primarily as enzyme inhibitors and 71 identifiable enzyme targets for these drugs. Although there are many enzyme inhibitors, most of them can be categorized into a relatively small number of distinct classes based on their general mode of action: competitive inhibitors, irreversible inhibitors, and allosteric inhibitors. Thinking about security, the pharmaceutical industry favors the development of competitive and allosteric inhibitors over that of irreversible inhibitors.
Fig.3 Mechanism of normal enzyme (a), competitive inhibitors (b), irreversible inhibitors (c), and allosteric inhibitors (d). (Blass, 2015)
It is widely accepted that enzymes are potential targets in novel drugs development. Creative Biolabs has exploited the area of new drug target discovery for over 10 years and gained some achievements. If you are interested in drug target development or other fields in therapeutic molecular development, please feel free to contact us.
Blass, B. E. Basic principles of drug discovery and development. Elsevier. 2015.
Robison, P. K. Enzymes: principles and biotechnological applications. Essays in biochemistry. 2015, 59, 1.