Chemical agents are used in both sterilization for the complete elimination of microbes and in disinfection for the reduction in the number of microbes on a surface or in a fluid. Chemical agents damage cellular structures, including, but not limited to, proteins, cell walls and membranes, and nucleic acids.Denaturation describes the process of unfolding the protein's shape, rendering it unfunctional. Chemical agents that affect proteins often do so by denaturing them. Denaturation affects the shape of the protein but not the sequence of the amino acids that make it up. However, because proteins rely on their shape in order to properly function, denaturation can bring cellular processes to a halt. Some chemical agents permanently alter the structure of the protein, making the agents germicidal. Others, however, alter the structure of the protein only when present and the protein can refold into its normal structure once the chemical agent is removed. These agents are microbiostatic, meaning they pause microbial growth but once the agent is removed the microbes will begin to grow again.
Chemical agents may also affect nucleic acids. Many chemical agents bind to nucleic acids or replace them in DNA and RNA sequences. This interferes with cell division and with the production of functional proteins. Chemical agents may also interrupt cellular pathways, especially those involved in cellular respiration and fermentation. This disrupts the cell's energy production, leading to cell death.