Protein

A body now known as alkali albumin, but originally considered to be the basis of all albuminous substances, whence its name.

A molecule composed of amino acids that perform many functions within an organism

any of a large group of nitrogenous organic compounds that are essential constituents of living cells; consist of polymers of amino acids; essential in the diet of animals for growth and for repair of tissues; can be obtained from meat and eggs and milk and legumes; "a diet high in protein"