Which of the following is not a target molecule for drug function in body?

Vitamins

The correct answer is Option (3) → Vitamins

Drugs interact with specific target molecules in the body to exert their effects. These target molecules typically include proteins, lipids, and carbohydrates. However, vitamins are usually not considered direct targets for drug action. Let's break down each category in more detail:

1. Carbohydrates (Occasional Drug Targets)

Drugs may occasionally interact with carbohydrate structures on cell surfaces. For instance, some antiviral drugs target glycoproteins (proteins with carbohydrate groups attached) on viruses to prevent them from attaching to host cells.

Cell Signaling and Recognition: Carbohydrates are involved in cell signaling, which can be a secondary target in drug design.

2. Lipids (Common Drug Targets)

Lipids are key components of cell membranes, and some drugs target lipid-based structures. For example, antibiotics like amphotericin B target the lipid membranes of fungi, disrupting their cell structure and killing them.

Cholesterol and Fat Metabolism: Statins, a class of drugs used to lower cholesterol, target HMG-CoA reductase, an enzyme involved in lipid metabolism, which indirectly affects lipid levels in the body.

3. Vitamins (Not a Typical Drug Target)

Vitamins are essential nutrients that help regulate various biochemical reactions in the body. However, vitamins themselves are not common targets for drugs. Instead, drugs may interact with enzymes or pathways that utilize vitamins as cofactors.

While vitamins like vitamin K are involved in blood clotting, drugs like warfarin target the enzymes in the blood clotting pathway rather than the vitamin itself. Vitamins act as cofactors or activators for these enzymes but are not directly altered by drugs.

Dietary Supplements vs. Drugs: Vitamins are more often taken as dietary supplements rather than pharmaceutical drugs. While important for overall health, they are not typically the molecules that drugs aim to modulate directly.

4. Proteins (Common Drug Targets)

Many drugs work by inhibiting enzymes. For example, non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin inhibit the enzyme cyclooxygenase, reducing inflammation and pain.

Drugs often bind to receptors on the surface of cells to activate or inhibit specific cellular responses. For example, beta-blockers bind to adrenergic receptors in the heart, reducing heart rate and blood pressure.

Drugs can target proteins involved in transporting molecules across cell membranes. For instance, antidepressants like SSRIs (selective serotonin reuptake inhibitors) target serotonin transport proteins to increase serotonin levels in the brain.

Conclusion:

Among the options provided:

Proteins, lipids, and carbohydrates can serve as direct drug targets because of their roles in cellular structures and biochemical pathways.

Vitamins, while essential for metabolic processes, are not primary targets for drug action. Drugs typically do not interact directly with vitamins but may affect the metabolic pathways that depend on them.

Thus, vitamins are the correct answer, as they are not a common direct target for drug function in the body