Amino acid composition of prolamins and the whole seed in representatives of 52 cereal genera and 22 tribes, as well as amino acid composition of seed protein fractions in representatives of 9 cereal genera are presented. In terms of proposed directed evolution of the seed proteins and adaptive role of prolamins in evolution and distribution of cereals, generalized data on their content in seed protein complex, electrophoretic, immunochemical, and amino acid composition of the seeds, we develop the notion of prolamins biochemical specialization and their polyphyletic origin during evolution of cereal seed protein complex. Seven adaptive types of prolamins are recognized: Sasa, Molinia, Chloris, Zingeria, Poa, Triticum, and Panicum types. Adaptive types of prolamins were formed in response to an ecological request of the environment where taxon ancestors existed and a taxon appeared and in relation to phylogenetic history of a taxon and its assignment to particular tribe and subfamily.