Characteristics of proteins from normal, high lysine, and high tannin sorghums

Abstract

The purpose of this paper was to study the charac~t.erirtics of proteins from normal, high lynint., and high tannin Sorghum hicolor (I,.) Mwnch. Endosperm preparations were otltained from four inbred lines of sorghum representing a normal, low tannin variety (P-7'21-N), its mutagenically derived high lysine counterpart (P-721-O), an inbred Ethiopian variety high in lysine (IS-1 1167), and a high tannin line (IS-4225). Endosperm proteins were separated into five soluhle fractions hy the Iandry Moureaux method. Whole endosperms and their respective protein fractions were nubjected 111 amino acid analysis. Polyacrylamide gel electrophoresiu patt.erns were determined for the fractionated prot.eins. The high lysine endosperms had lower levels of kafirins (fractions I1 and 111) than the lysine-deficient, alcohol-soluble protein fraction, when compared with the normal sorghum endosperm preparations. Both high lysine varieties contained elevated leveh of alhuminn and glohulins (fraction I) and glutelins (fraction V), which were the highest in lysine content. Differencw from normal were o k r v d in the distribution pattern of proteins from a high tannin sorghum. There were no significant differences among the constituent proteins of the identical fractions of these four varieties of sorghum an determined hy gel electrophoresis. These results support the general hypothesin that genen affecting protein quality do no by changing the relative quantities of 1.andry Moureaux fractions and not by changing the quality of proteins within these fractions.

Effect of suppressing the synthesis of different kafirin sub-classes on grain endosperm texture, protein body structure and protein nutritional quality in improved sorghum lines

“…The TG lines and their respective null controls were all generally very similar or even identical in protein content. The protein contents reported here are well within the range for native Ethiopian high-lysine sorghums (10.0-17.2%) (Guiragossian et al, 1978;Singh and Axtell, 1973), high protein digestibilityhigh lysine mutant sorghums (10.2-14.7%) (Tesso et al, 2006;Weaver et al, 1998) and normal sorghums (8.1-16.8%) (reviewed by Rooney and Serna-Saldivar, 1990). …”

“…The high lysine TG lines also showed considerable reduction in proline (24% lower), alanine (17%), glutamic acid/glutamine (15%), leucine (15%) and phenylalanine (15%), and increases in arginine (76% higher), aspartic acid (48%), methionine (42%) and glycine (32%) compared to the normal sorghums (Table 3). Similar changes in the amino acid profile of high-lysine cereals have been reported (Guiragossian et al, 1978;Singh and Axtell, 1973;Vendemiatti et al, 2008;Zarkadas et al, 2000). The altered amino acid profile observed for TG-P898012 (ABS032) and the backcrosses is probably a direct consequence of co-suppression of the synthesis of the major kafirin sub-classes.…”

“…The lysine content of TG-P898012 (ABS032) and the backcrosses were slightly higher than that reported for native Ethiopian high-lysine genotypes (3.2-3.7 g/100 g protein) (Guiragossian et al, 1978;Singh and Axtell, 1973), and high protein digestibility-high lysine mutant sorghums (2.9-3.4 g/100 g protein) (Tesso et al, 2006;Weaver et al, 1998). But lysine values were in the range reported for quality protein maize (QPM) cultivars (3.43-4.56 g lysine/100 g protein) (Zarkadas et al, 2000).…”

“…Because the kafirins contain essentially no lysine, these results indicate a substantial increase in the proportion of non-kafirin storage proteins and non-storage proteins in the grain, which are higher in lysine content. In other high-lysine sorghum genotypes, the proportion of lysine rich non-kafirin storage proteins (albumins, globulins and glutelins) was considerably higher compared to normal sorghums (Guiragossian et al, 1978;Vendemiatti et al, 2008). While in high-lysine opaque-2 mutant maize genotypes, the increase in lysine content is attributed to elongation factor-1α (EF-1α), a lysine rich (11% lysine) non-zein protein (Habben et al, 1995).…”

Padrões eletroforéticos das proteínas de reserva em grãos de sorgo com presença e ausência de tanino

“…Esse fato ocorreu durante o procedimento de centrifugação após as amostras serem agitadas para a extração das proteínas. A alteração de forma quantitativa no fracionamento das albuminas, globulinas e prolaminas também foi observada por Guiragossian et al (1978) e Jambunathan & Mertz (1973. Na Figura 1, observa-se também o padrão proteico das proteínas classificadas como albuminas e globulinas para a variedade de milho BR 106 (coluna 2).…”