Chapter 6: Cereal grain proteins

Proteins are essential for the structure, development, and function of the plant cell. They include structural proteins in the membranes of cells and organelles, transporters that move components between and within cells and tissues, enzymes, components that capture and transfer energy (in mitochondria and chloroplasts) and components that regulate gene expression and metabolism. With very few exceptions, all proteins consist of 20 amino acids, which contain amino ( NH2) and carboxyl ( COOH) functional groups, together with side chains specific for each amino acid. The side chains differ in their properties, allowing the amino acids to be classified into types (Box 6.1). The individual amino acids are assembled into chains by the formation of peptide bonds between the carboxyl and amino groups, resulting in the loss of a molecule of water. The sequences of the individual amino acids determine the folded protein structures and the biological functions of the proteins.