The glutelin-2 (G2) fraction from maize endosperm has been purified and antibodies obtained against its main polypeptide component (28 kilodalton (kD) G2). These antibodies have been used to establish the relationship between 28 kD G2 and zein-2 (Z2) low molecular weight polypeptides (14 kD Z2, 10 kD Z2) that were also purified. We have observed by immunoblotting that the anti-glutelin-2 sera crossreact with one of Z2 polypeptides (14 kD Z2). The specificity of immunoreactions has been determined by the enzyme-linked immunosorbent assay (ELISA). Affinity-purified antibodies recovered from 28 kD G2 and 14 kD Z2 immunoblotting bands cross-react with both polypeptides, suggesting the presence of common antigenic determinants. Both the immunological data and the high cysteine content indicate that they are related polypeptides that might have common functions inside the storage reservoirs of maize endosperm cells. This research was supported by grants from Fundacion Ramon Areces, Comision Asesora de Investigacion Cientifica y Tecnica and CIRIT from the Generalitat de Catalunya. Peer reviewed