Arginine is a basic amino acid that is found in the active centers of proteins. It binds phosphorylated substrates and is good at binding phosphate anions. It has a positively charged guanidino group that helps with the process.
It is a polar molecule that is attracted to water. Since it is a cation, arginine helps maintain the overall charge balance of a protein. Arginine has an important role in nitrogen metabolism. There are six codon sequences that code for arginine in DNA, but it is one of the most infrequently found amino acids. Amino acids are the subunits of proteins, and the R groups on the individual amino acids give them each distinct properties.