**5.4 Glutelins**

Glutelins are the member of the class of prolamin proteins. The seed endosperm of the grass family is mostly enriched with glutelin proteins. Gluten is the main component of the glutelin protein. Zhao et al. [60] established that about 70–80% glutelins are present mostly in rice. They also reported that glutelins are homologous to 11-12S globulin proteins of leguminous family. Wakasa *et al.*, [61] explained that the pre-proglutelins are the initial precursor of glutelins and due to hydrophobic interactions in the lumen of the rough endoplasmic reticulum they form homotrimers and heterotrimers. [62] reported the 15 glutelin genes in the rice genome, and classified them on the basis of their amino acid sequences into four groups- Glu A, Glu B, Glu C, and Glu D. Glu A consists of three members Glu A1, Glu A 2 and Glu A 3 and Glu B have four members Glu B1, Glu B2 Glu B3 Glu B4. Takahashi *et al*., [63] demonstrated the localization pattern of five subtypes of the glutelin protein in rice grains with the help of glutelin-subtype specific antibodies. They reported that the localization of GluA was strongly in the outer region of the endosperm, including the subaleurone layer, and that of GluC was localized throughout the endosperm.
