Maize Endosperm Proteins That Contribute to Endosperm Lysine Content

Abstract

ABSTRACTNonzein proteins were analyzed using SDS‐PAGE to study their relationship to lysine level in mature endosperm of three isogenic lines and 29 inbred lines. The majority of nonzein proteins are glutelins that contain a relatively high lysine content. Trinitrobenzene‐sulfonic acid was used to visualize high‐lysine proteins on nitrocellulose membrane. Seven intense yellow bands (high‐lysine proteins) were found in the glutelin fraction: 35, 43, 48, 52, 84, 92, and 100 kDa. These seven glutelin proteins were also significantly correlated to each other. Lysine content of the triads correlated with three glutelin proteins (35, 43, and 52 kDa), while lysine content of 29 inbred lines correlated with six glutelin proteins (all except 52‐kDa protein). Immunoassays based on these higher lysine glutelin proteins provide an effective screening method in the presence of variable zein levels. Retention or improvement of lysine content is possible using this information in a maize improvement program.