Valine is an α-amino acid that is used in the biosynthesis of proteins. It is essential in humans, meaning the body cannot synthesize it. It contains an α-amino group, an α-carboxylic acid group, and a side chain isopropyl group, making it a non-polar aliphatic amino acid. Valine is in soy, cheese, peanuts, mushrooms, whole grains, and vegetables. Isoleucine is plentiful in meat, fish, poultry, eggs, cheese, lentils, nuts, and seeds. Dairy, soy, beans, and legumes are sources of leucine (see: Wikipedia).