Proteinaceous part of maize endosperm is
Maize is a monoctyledonous endospermic seed. In monocotyledonous endospermic seed, endosperm is surrounded by a special one- cell thick layer, called aleurone layer. The cells of aleurone layer are filled with proteinaceous aleurone grains which play an important role at the time of germination. So, the correct answer is 'Aleurone layer'.