Applications

Small molecules are low molecular weight (<900 daltons) organic compound that may help regulate a biological process, with a size on the order of nanometer. Most commercial drugs are small molecules. Small molecules can have a variety of biological functions, serving as cell signaling molecules, as drugs in medicine, as pesticides in farming, and in many other roles. Peptides are distinguished from proteins on the basis of size, they contain approximately 50 or fewer amino acids. Peptides allow the creation of peptide antibodies in animals without the need of purifying the protein of interest. Peptides can also be used in mass spectrometry for the identification of proteins of interest based on peptide masses and sequence. (Source Wikipedia)