Protein Glutelin Research Articles

Heterogeneity in cDNA clones encoding rice glutelin

Clones encoding the rice storage protein glutelin were selected from a cDNA library of immature rice seeds. Sequence analysis and hybridization studies on these clones provide insight into the nature of heterogeneity in glutelin genes. Based particularly on major differences in the 3′-noncoding regions, it appears that glutelin genes fall into two sub-families.

Immunochemical studies on the role of the Golgi complex in protein-body formation in rice seeds

Antibodies raised against purified glutelins and prolamines were employed as probes to study the cellular routes by which these proteins are deposited into protein bodies of rice (Oryza sativa L.) endosperm. Three morphologically distinct protein bodies, large spherical, small spherical, and irregularly-shaped, were observed, in agreement with existing reports. Immunocytochemical studies showed the presence of glutelins in the irregularly-shaped protein bodies while the prolamines were found in both the large and small spherical protein bodies. Both the large and small spherical protein bodies, distinguishable by electron density and gold-labeling patterns, appear to be formed by direct deposition of the newly formed proteins into the lumen of the rough endoplasmic reticulum (ER). In contrast, glutelin protein bodies are formed via the Golgi apparatus. Small electron-lucent vesicles are often found at one side of the Golgi. Electron-dense vesicles, whose contents are labeled by glutelin antibody-gold particles, are commonly observed at the distal side of the Golgi apparatus and fuse to form the irregularly shaped protein bodies in endosperm cells. These observations indicate that the transport of rice glutelins from their site of synthesis, the ER, to the site of deposition, the protein bodies, is mediated by the Golgi apparatus.

The structure of rice storage protein glutelin precursor deduced from cDNA

The complete amino acid sequence of rice storage protein glutelin was determined by the sequencing of the corresponding cDNA. The deduced glutelin precursor has a 37 amino acid signal peptide sequence at the NH 2 terminus, which is followed by a 269 amino acid acidic subunit ( M r = 32 489) and a 193 amino acid basic subunit ( M r = 19 587). The glutelin precursor sequence is homologous to those of pea legumin and soybean glycinin.

Structural Relationship among the Rice Glutelin Polypeptides

When the glutelin protein fraction of rice (Oryza sativa L.) seeds was fractionated by sodium dodecyl sulfate polyacrylamide gel electrophoresis, three size classes of proteins, 51 kilodaltons (kD), 34 to 37 kD, and 21 to 22 kD, as well as a contaminating prolamine polypeptide of 14 kD were detected. Antibodies were raised against these proteins and employed in studies to determine whether a precursor-product relationship existed among the glutelin components. Antibodies of the 34 to 37 kD and 21 to 22 kD polypeptides strongly reacted with the 51 kD protein, and conversely, anti-51 kD protein cross reacted with both of the putative subunits. Immunoprecipitation of in vitro translated products resulted in the synthesis of only the precursor form, indicating that the alpha and beta subunits are proteolytic products of the 51 kD precursor protein. The poly(A)(+) RNA directed in vitro translated product was about 2000 daltons larger than both the authentic glutelin precursor and the in vitro translated product from polysome run-off synthesis. Western blot analysis of the 34 to 37 kD and 21 to 22 kD polypeptides partially digested with Staphylococcus aureus V8 protease revealed distinct patterns indicating that these proteins are structurally unrelated. As observed for the glutelins, the rice prolamines are also synthesized as a precursor of 16 kD, 2000 daltons larger than the mature polypeptide. Addition of dog pancreatic microsomal membranes to a wheat germ protein translation system resulted in the processing of the prolamine preprotein but not the preproglutelin to the mature form.

Effect of malting on the protein and free amino nitrogen composition of sorghum

AbstractWhen sorghum is malted much of the nitrogen in the kernel is transferred to the roots and shoots. Examination of Osborne protein fractions extracted from the kernel reveals that as in the case of barley the prolamins are the major source of the nitrogen transferred. Electrophoretic prolamin bands remained unchanged during malting, indicating that prolamins are degraded directly to small peptides and amino acids. There was a general decline in the number of glutelin proteins whereas some albumin plus globulin proteins increased in quantity while others decreased. In the roots and shoots there was a considerable increase in both protein nitrogen and non‐protein nitrogen as a result of the translocation of the products of storage protein breakdown from the kernel. Several‐fold increases occurred in all of the nine essential amino acids determined. Quantitatively, the two most important free amino acids of sorghum malt appear to be asparagine and glutamine, as in germinated wheat and maize. This is in contrast to barley where proline is the major free amino acid.

The nutritional value of high-lysine barley genotypes

The protein quality of some improved high-lysine barley genotypes was measured chemically — including amino acid analyses and sequential protein extraction — and biologically in N-balance experiments with growing rats. The increased content of lysine, mainly due to an enhancement of the glutelin protein fraction, and other essential amino acids improved the nutritional quality as the biological value of the protein was significantly higher in the high-lysine material compared to normal. This improvement is undoubtedly of importance to meet the essential amino acid requirement of man as well as monogastric animals.

Influence of Opaque-2 and Floury-2 Genes on Formation of Proteins in Particulates of Corn Endosperm

Protein-rich subcellular particulates were isolated by zonal centrifugation from homogenates of endosperms of normal, opaque-2, and floury-2 mutant corn (Zea maize) kernels at different stages of development. In early stages the high lysine mutants vary from normal corn by greater production of a glutelin protein not associated with the matrix. This protein is high in lysine and may become a component of matrix glutelin at later stages of maturity. Differences in size and structure of zein-rich protein bodies were observed in the mutant strains when compared with normal corn. Enhanced production of nonmatrix glutelin as well as the reduction in synthesis of lysine-deficient zein is responsible for the improved lysine content of the mutant endosperms at early stages of development.

Fractionation and properties of alkylated-reduced corn glutelin proteins

The disulfide bonds of glutelin protein from corn endosperm were cleaved to yield polypeptide chains which were subjected to physical and chemical investigations. After reduction with mercaptoethanol and alkylation with acrylonitrile of resulting sulfhydryls, about 87% of the protein was soluble in 6 M guanidine-HC1 and 47% in 0.3 M acetic acid, whereas native protein was much less soluble in both solvents. Gel filtration chromatography on different media with those solvents established that the polypeptide chains were heterogeneous in molecular weight and appeared to aggregate in the acetic acid. Fractionation of the alkylated-reduced glutelin by repeated chromatography on Sephadex G-200 in 6 M guanidine-HC1 yielded six peaks with components that differed in electrophoretic mobilities on starch gel. Direct extraction with 70% ethanol of the alkylated-reduced protein complex yielded a fraction that contained components mainly present in three of the Sephadex chromatography peaks and were similar in some properties to zeins. Molecular weight, gel electrophoretic mobilities and amino acid compositions of all of the isolated fractions indicate that glutelin consists of a series of unique proteins which form a structural matrix stabilized by disulfide bonds in mature corn endosperm.

Comparison of glutelin proteins in normal and high-lysine corn endosperms

Comparison of glutelin proteins in normal and high-lysine corn endosperms

Corn Glutelin Protein as a Source of Amino Acids for the Growing Chick

ABSTRACT THE use of plant materials as protein sources for poultry rations is now widespread. The most commonly used material of this type is soybean oil meal, although its use in poultry diets necessitates the addition of supplements to augment its deficiency in sulphur containing amino acids (Bird and Mattingly, 1945; Clandinin et al., 1946; Gerry et al., 1948; Milligan et al., 1951; and Machlin et al., 1952). Many products have been tested as possible sources of protein to replace soybean oil meal in chick diets. Acceptance or rejection of a supplement is usually dependent upon its amino acid content and availability. The present investigation was initiated to study the content and availability of the amino acids in corn glutelin protein and its value as a protein supplement for chick rations. EXPERIMENTAL All amino acid determinations were carried out microbiologically according to the method of Kuiken and Lyman (1948). Availability tests . . .

Effect of heat on solvent‐extracted soybean oil meal

AbstractAs a result of this investigation it appears that if the relationship between the nutritional value of soybean oil meal and its protein glutelin fraction is confirmed for a wider range of processing conditions than those reported on by Evans and St. John (5), there then exists a simple, reliable, and reproducible analytical means of further relating nutritional value to plant processing conditions. For the range of processing conditions normally employed in plant practice, a maximum glutelin fraction percentage is consistently attained with the application of either dry or moist heat, beyond which additional heat treatment results in a decrease, completing a pattern with heating similar to that normally followed by the nutritional value of the meal. In all cases where moist heat was employed, the activity of both the urease and lipoxidase enzyme systems was reduced to a level satisfactory for feeding prior to the point where the maximum glutelin protein fraction was attained. This is in agreement with numerous poultry feeding tests relating feed value to processing conditions.

FREE AMINO ACIDS IN THE DEVELOPING ENDOSPERM OF MAIZE

UNDERSTANDING the metabolism of the developing maize endosperm is a problem of practical and theoretical importance. Carbohydrate metabolism in the maize endosperm has been investigated extensively by means of various biochemical and genetic techniques (Culpepper and Magoon, 1924, 1927; Bernstein, 1943; Sprague et aL, 1943; Andrew et al., 1944; Cameron, 1947; Kramer and Whistler, 1949), but nitrogen metabolism of the endosperm has remained relatively unexplored. Zeleny (1935) and Watson (1949) have shown that endosperm proteins (largely zein and glutelin) are synthesized during the entire kernel maturation period, but that most of the glutelin (alkali-soluble) proteins are synthesized during the first half, and most of the zein complex of proteins (alcohol-soluble) during the last half of the endosperm maturation period. Biochemical genetics studies (Showalter and Carr, 1922; Frey et al., 1949; Frey, 1951) and analyses of various varieties and genotypes of maize endosperm (Hansen et al., 1945) show that there is a direct correlation between the content of zein and of total protein in the endosperm; this mav indicate that alcohol-soluble proteins are the major storage proteins of the endosperm. Interrelations of tryptophan, niacin and indoleacetic acid in the developing maize endosperm have been investigated by Stehsel and Wildman (1950). Their studies are perhaps the first attempt to explore the nitrogen metabolism of the developing maize endosperm on the level of individual enzymesubstrate-product reactions. It is only on this level that one can investigate adequately the various metabolic processes of the developing endosperm. Thus, a working knowledge of the kinds and amounts of nitrogenous components in the endosperm throughout its development is fundamental to understanding endosperm protein synthesis. This study is a preliminary investigation of the free amino acids and amides of the developing endosperm of four varieties of corn. Partition paper chromatography, an analytical technique proven to be useful for rapid surveys of kinds and approximate amounts of amino acids in other plant tissues (Dent et al., 1947) has been adapted for use in this investigation. MATERIALS AND METHODS.-Four morphologically dissimilar varieties of maize: Longfellow Flint,