Target biological structures : the cell, organelles, DNA and RNA

Living organisms are self replicating molecular factories of staggering complexity. As a result, we are often overwhelmed when trying to identify potential targets for therapeutics. Water, inorganic ions and a large array of relatively small organic molecules (e.g., sugars, vitamins and fatty acids) account for approximately 80% of living matter, with water being the most abundant. Macromolecules such as proteins, polysaccharides, ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) constitute the rest. The majority of potential therapeutic targets are found within the cell. Small molecules which are vital for cellular function are imported into the cell by a variety of mechanisms but unlike smaller molecules, macromolecules are assembled within the cell itself. Drugs are usually designed to target cellular macromolecules, as they perform very specific roles in the metabolic process.