ENZYMOLOGY

PRESENTED BY GROUP 8

ENZYME

�Enzymes are proteins that help speed up chemical reactions in our bodies. Enzymes are essential for digestion, liver function and much more.

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• Eg. The enzyme pepsin is a critical component of gastric juices, helping to break down food particles in the stomach. Likewise, the enzyme amylase, which is present in saliva, converts starch into sugar, helping to initiate digestion. In medicine, the enzyme thrombin is used to promote wound healing.

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MECHANISM OF ENZYME ACTIONS

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Enzymes are biological molecule typically protein that catalyst specific chemical reaction the mechanism of enzyme action involve several steps

Substrate binding

The enzymes recognize and bind to it substrate, positioning it for catalysis

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Active site

The substrate bind to the active site, a specific region on the enzyme surface which is shaped to optimized the interaction

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Confirmation change

The enzyme undergoes a conformational change positioning the substrate for catalysis

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Catalysis

The enzymes facilitate the chemical reaction often using cofactor or coenzyme

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Product release

The product is released for the active side allowing the enzyme to bind with new substrate molecule

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Enzymes turn over

The enzyme can repeat the process catalyzing multiple process

Enzymes mechanism of action are often described by following model

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Lock and key model:

the active site is perfect fit for the substrate

Induce fit model:

the active site adopts to the substrates creating a perfect fit

Understanding enzymes mechanism is circular for field like biochemistry molecular biology and drug developments.

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ACTIVATOR AND INHIBITOR

Activators

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• Bind to specific sites on enzymes or proteins increasing their activity Enhance substrate binding or catalytic efficiency-
• Can increase gene expression by binding to transcription factors or enhancer regions-
• Examples:
• - Allosteric activators (e.g., oxygen binding to hemoglobin)
• - Coenzymes (e.g., NAD+ in glycolysis)
• - Transcriptional activators (e.g., cyclic AMP response element-binding protein (CREB))

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Inhibitors

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• Bind to specific sites on enzymes or proteins, decreasing their activity-
• Can reduce substrate binding or catalytic efficiency-
• Can decrease gene expression by binding to transcription factors or silencer regions-

Examples:

• - Competitive inhibitors (e.g., methotrexate inhibiting dihydrofolate reductase) -
• Non-competitive inhibitors (e.g., cyanide inhibiting cytochrome c oxidase)
• - Transcriptional inhibitors (e.g., histone deacetylases)

HERE ARE SOME MORE DETAILS ON FACTORS AFFECTING ENZYME ACTIVITY �

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1. Temperature:

Temperature plays a crucial role in enzyme activity. As the temperature increases, the rate of enzyme-catalyzed reactions generally increases as well. However, extreme temperatures can denature enzymes, causing them to lose their shape and function.

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2. pH Levels:

The pH level, or acidity/alkalinity, of the environment also affects enzyme activity. Enzymes have an optimal pH range in which they function most effectively

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3. Substrate Concentration:

The concentration of the substrate, or the molecule that the enzyme acts upon, can significantly impact enzyme activity.

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4. Enzyme Concentration:

The concentration of enzymes in a reaction also affects the rate of enzyme activity. Generally, as the enzyme concentration increases, the reaction rate increases as well, assuming that there is an excess of substrate available.

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COENZYMES AND ITS CLASSIFICATIONDS

• Coenzymes are organic molecules that assist enzymes in catalyzing reactions. They often work by transferring chemical groups from one molecule to another.

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HERE ARE SOME COMMON CLASSIFICATIONS OF COENZYMES:��

• 1 Cosubstrates:

These are transiently bound to the enzyme during the reaction and are chemically altered during the reaction. Examples include coenzymes such as NAD+ (nicotinamide adenine dinucleotide) and FAD (flavin adenine dinucleotide), which carry electrons during redox reactions.

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2 Prosthetic groups:

These are tightly bound to the enzyme and participate in the reaction permanently. Examples include heme in catalase and biotin in enzymes involved in carboxylation reactions.

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3. Cofactors:

These are inorganic ions or small molecules that assist enzymes. Examples include metal ions like Mg2+, Zn2+, and Fe2+.

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4. Activators:

Some molecules bind to enzymes and induce a conformational change, increasing the enzyme's activity. These are not strictly coenzymes but can function similarly. Examples include ions like Ca2+ and molecules like ATP.These classifications help in understanding the diverse roles coenzymes play in various biochemical reactions.

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ENZYMES PLAY CRUCIAL ROLES IN CLINICAL MEDICINE ACROSS VARIOUS FIELDS

Diagnostic Enzymes:

Enzyme assays are commonly used in diagnostics to detect specific biomarkers indicative of disease or organ damage. For example, elevated levels of enzymes like creatine kinase (CK), lactate dehydrogenase (LDH), and amylase can indicate heart damage, tissue injury, or pancreatic disorders, respectively.

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Therapeutic Enzymes:

Enzyme replacement therapy (ERT) involves administering specific enzymes to patients who are deficient in those enzymes due to genetic disorders. For instance, in diseases like Gaucher's disease, Fabry disease, and Pompe disease, ERT aims to alleviate symptoms and improve quality of life.

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Pharmacological Enzyme Inhibitors:

Enzyme inhibitors are used as drugs to modulate enzymatic activity in the body. For example, inhibitors of enzymes like angiotensin-converting enzyme (ACE) and HMG-CoA reductase are widely used in the treatment of hypertension and hypercholesterolemia, respectively.

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Biocatalysts:

Enzymes are used in the synthesis of pharmaceuticals and drug intermediates. Enzymatic reactions often offer higher selectivity and milder reaction conditions compared to traditional chemical synthesis methods, leading to more efficient and environmentally friendly processes.

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Targeted Therapy:

Enzymes are increasingly being targeted for therapeutic purposes, especially in cancer treatment. For example, drugs known as enzyme inhibitors may target specific enzymes involved in cancer cell proliferation or angiogenesis, helping to inhibit tumor growth.Overall, enzymes have become

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indispensable tools in clinical medicine, both for diagnosis and treatment, and ongoing research continues to uncover new ways to harness their potential in medical practice.

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