Maize endosperm proteins that contribute to endosperm lysine content

Nonzein proteins were analyzed using SDS-PAGE to study their relationship t o lysine level in mature endosperm of three isogenic Lines and 29 inbred li nes. The majority of nonzein proteins are glutelins that contain a relative ly high lysine content. Trinitrobenzene-sulfonic acid was used to visualize high-lysine proteins on nitrocellulose membrane. Seven intense yellow band s (high-lysine proteins) were found in the glutelin fraction: 35, 43, 48, 5 2, 84 92, and 100 kDa. These seven glutelin proteins were also significantl y correlated to each other. Lysine content of the triads correlated with th ree glutelin proteins (35, 43, and 52 kDa), while lysine content of 29 inbr ed lines correlated with six glutelin proteins (all except 52-kDa protein). Immunoassays based on these higher lysine glutelin proteins provide an eff ective screening method in the presence of variable zein levels. Retention or improvement of lysine content is possible using this information in a ma ize improvement program.