MODIFICATION OF MAIZE-SEED-PROTEIN QUALITY

The storage proteins of maize are a group of alcohol-soluble polypepti des called zeins. These proteins are synthesized in the developing end osperm, where they form protein bodies within the rough endoplasmic re ticulum. Because they account for more than half of the total seed pro tein, zeins are the primary determinants of the amino acid composition of the seed. All of the zeins are devoid of lysine, an essential amin o acid for monogastric animals. We have modified the genes encoding ze ins so that they encode proteins that contain lysine and tryptophan. A nalysis of the synthesis and processing of these modified zein protein s indicates that the addition of lysine and tryptophan does not interf ere with their association into protein bodies.