High-lysine corn produced by the combination of enhanced lysine biosynthesis and reduced zein accumulation.

Corn is one of the major crops in the world, but its low lysine content is often problematic for animal consumption. While exogenous lysine supplementation is still the most common solution for today's feed corn, high-lysine corn has been developed through genetic research and biotechnology. Reducing the lysine-poor seed storage proteins, zeins, or expressing a deregulated lysine biosynthetic enzyme, CordapA, has shown increased total lysine or free lysine content in the grains of modified corn plants, respectively.

High lysine and high tryptophan transgenic maize resulting from the reduction of both 19- and 22-kD alpha-zeins.

The major maize seed storage proteins, zeins, are deficient in lysine and tryptophan content, which contribute to the poor nutritional quality of corn. Whether through the identification of mutations or genetic engineering, kernels with reduced levels of zein proteins have been shown to have increased levels of lysine and tryptophan. It has been hypothesized that these increases are due to the reduction of lysine-poor zeins and a pleiotropic increase in the lysine-rich non-zein proteins.