title: Regulation of lysine metabolism and endosperm protein synthesis by the opaque-5 and opaque-7 maize mutations.
abstract: Two high lysine maize endosperm mutations, opaque-5 (o5) and opaque-7 (o7), were biochemically characterized for endosperm protein synthesis and lysine metabolism in immature seeds. Albumins, globulins, and glutelins, which have a high content of lysine, were shown to be increased in the mutants, whereas zeins, which contain trace concentrations of lysine, were reduced in relation to the wild-type lines B77xB79+ and B37+. These alterations in the storage protein fraction distribution possibly explain the increased concentration of lysine in the two mutants. Using two-dimensional polyacrylamide gel electrophoresis of proteins of mature grains, variable amounts of zein polypeptides were detected and considerable differences were noted between the four lines studied. The analysis of the enzymes involved in lysine metabolism indicated that both mutants have reduced lysine catabolism when compared to their respective wild types, thus allowing more lysine to be available for storage protein synthesis.
authors.affiliation: Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, and Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Piracicaba CEP 13418-900, SP, Brazil. raazeved@esalq.usp.br
authors.forename: Ricardo A
authors.initials: RA
authors.lastname: Azevedo
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Lea
authors.forename: Catherine
authors.initials: C
authors.lastname: Damerval
authors.forename: Jacques
authors.initials: J
authors.lastname: Landry
authors.forename: Cláudia M
authors.initials: CM
authors.lastname: Bellato
authors.forename: Lyndel W
authors.initials: LW
authors.lastname: Meinhardt
authors.forename: Martine
authors.initials: M
authors.lastname: Le Guilloux
authors.forename: Sonia
authors.initials: S
authors.lastname: Delhaye
authors.forename: Vanderlei A
authors.initials: VA
authors.lastname: Varisi
authors.forename: Salete A
authors.initials: SA
authors.lastname: Gaziola
authors.forename: Priscila L
authors.initials: PL
authors.lastname: Gratão
authors.forename: Alejandro A
authors.initials: AA
authors.lastname: Toro
mesh_terms: D015180:Electrophoresis, Gel, Two-Dimensional; D005838:Genotype; D008239:Lysine / Q000378:metabolism*; D009154:Mutation; D010940:Plant Proteins / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*; D012639:Seeds / Q000378:metabolism; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism; D015028:Zein / Q000032:analysis / Q000235:genetics
chemical_list: D010940:Plant Proteins; D015028:Zein; D008239:Lysine