This is where the study of proteins proteomics comes in. Genes don t do anything by themselves except hold the blueprints for proteins. In addition, while there are in the order of 100,000 genes, there are probably millions of different proteins. They come in a multitude of different forms, from muscle tissue to enzymes and hormones that regulate body functions. Chemically, a protein is a complex molecule, composed of carbon, hydrogen, oxygen and usually, sulphur.
Some proteins also incorporate phosphorous, iron, zinc and copper.
These basic elements combine into molecules called amino acids, which are the building blocks of proteins. In plants, however, in addition to their 20 basic amino acids, over 250 non-protein amino acids can be present. These non-protein amino acids, also known as secondary metabolites, are intermediates in the synthesis or breakdown of protein amino acids. Many of these secondary metabolites are thought to play a role as defensive agents. To make a protein, amino acids are linked together in a chain, and each link has a different function.