[Extraction and characterization of grain prolamins of 6 sorghum Sorghum bicolor L. Moench cultivars].
The purpose of this work was to isolate and characterize prolamines from grains of sorghum, by their solubility and molecular properties. One variety, Zaraza-1 (SV-V51), and five hybrids (Dekalb-55, Dekalb-64, Wac-5005, Pioneer-815B and Savanna-5) were used. The prolamines, called kafirins, were extracted with 70% isopropanol at 60 degrees C, and then fractionated by two methods: 95% ethanol and gel filtration with Sephadex G-200. The molecular weight was determined by electrophoresis in a discontinuous polyacrylamide gel with sodium dodecyl sulfate (PAGE-SDS). The alpha kafirin (soluble fraction in 95% ethanol), and 7.13% of the grain's total protein, and the beta kafirin represents 21.64% of kafirin (the insoluble fraction), represents 78.36% of the kafirin and 25.39% of total protein. Three fractions were obtained from the column fractionation, two important ones (A and C), and one (B) in a lesser amount. The proportion of these fractions varied between cultivars, so that in SV-V51, D-64 and Wac-5005, A is predominant, and in high tannin sorghum, C is the predominant one. Kafirins reduced with 2-mercaptoethanol were separated in four subunits with molecular weights of: 15,000, 21,300, 24,300 and 51,500 daltons. Unreduced kafirin showed a larger number of subunits (six) whose molecular weights were: 15,000, 24,300, 48,500, 69,000, 80,000 and 93,500 daltons. Reduced and kafirin showed the same number of subunits as those of nonfractioned kafirin reduced with 2-mercaptoethanol.
Ortíz de Bertorelli
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Instituto de Química y Tecnología, Facultad de Agronomía (UCV), Maracay, Venezuela.
D005591:Chemical Fractionation; D002850:Chromatography, Gel; D002523:Edible Grain / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification*; D055315:Prolamins; D012995:Solubility
D010940:Plant Proteins; D055315:Prolamins
Extracción y caracterización de las prolaminas del grano de seis cultivares de sorgo Sorghum bicolor L. Moench.