In molecular biology, an arginine finger is an amino acid residue of some enzymes. Arginine fingers are often found in the protein superfamily of AAA+ ATPases, GTPases, and dUTPases, where they assist in the catalysis of the gamma phosphate or gamma and beta phosphates from ATP or GTP, which creates a release of energy which can be used to perform cellular work. They are also found in GTPase-activating proteins (GAP). Thus, they are essential for many forms of life, and are highly conserved. Arginine fingers function through non-covalent interactions. They may also assist in dimerization, and while they are found in a wide variety of enzymes, they are not ubiquitous.