The present invention is directed to compositions and methods for altering the levels of seed proteins in seed or grain. The invention is directed to the alteration of seed protein levels in plants, resulting in grain and seed with increased digestibility/nutrient availability, improved amino acid composition/nutritional quality, increased response to feed processing, improved silage quality, and increased efficiency of wet milling. The invention is further directed to nucleotide sequences encoding a sorghum delta-kafirin2 protein, sequences encoding a sugar cane delta prolamin2 protein, sequences encoding a sorghum LKR protein, and the amino acid sequences so encoded. Methods of using such sequences are also provided.