02413naa a2200313 a 450000100080000000500110000800800410001910000180006024501340007826000090021252015420022165000090176365000220177265000230179465000100181765000100182765000140183765000140185165000120186565000130187765300100189065300100190065300120191065300120192265300090193470000170194370000190196077301200197914745722018-06-11       1992    bl uuuu     u00u1 u    #d1 aHABBEN, J. E.  aCharacterization of genes that modify maize seed proteins and enhance the amino acid quality of the grain.h[electronic resource]  c1992  aSeeds of cultivated plants generally contain between 10 and 30% protein by dry weight. Greater than half of this protein is stored protein, which is accumulated to provide nitrogen and sulfur for the embryo when it germinates. Storage proteins are also an important source of amino acids for human and livestock nutrition. Consequently, there has been a long-term interest in finding methods to improve the quantity and quality of these seed proteins. Because of their abundance, storage proteins are the primary determinants of the amino acid composition of seeds. These proteins contain high proportions of glutamine and asparagine, which increase the capacity of the seed to store nitrogen. Unfortunately, storage proteins typically are devoid of several amino acids that are essential for human and non-ruminant livestock nutrition. Cereal seeds contain limiting amounts of lysine and tryptophan, while legume seeds are deficient in methionine and cysteine. Amino acid deficiencies can develop in diets predicated primarily on one type of grain. This problem can be alleviated by mixing cereal and legume proteins or by supplementing essential amino acids, but it would be ideal if each type of grain contained a balance of essential amino acids. Although a great deal of research has been devoted to the nutritional improvement of seed storage proteins, to a large extent this work has not been very successful. While it has been possible to increase the protein content of seeds through breeding, this approach has had little (...)  acorn  amolecular biology  aBiologia Molecular  aGrão  aMilho  aProteína  aQualidade  aSemente  aZea Mays  aGrain  aMaize  aProtein  aQuality  aSeed1 aLOPES, M. A.1 aLARKINS, B. A.  tIn: TAKAI, K. (Ed.). Frontiers and new horizons in amino acid research. New York: Elsevier Science, 1992. p. 57-64.