Proteins cereal prolamines

GL Lookhart, Y Pomeranz. Characterization of oat species by polyacrylamide gel electrophoresis and high performance liquid chromatography of their prolamin proteins. Cereal Chem 62 162-166, 1985. 

Cereal prolamins, named glutenins and gliadins in wheat, secalins in rye, and horde-ins in barley, are major storage proteins of the cereal grain endosperm. These sulfur-rich proteins comprise an N-terminal domain of proline- and glutamin-rich repeats and a C-terminal domain responsible for intrachain disulfide bonds (Breiteneder and Radauer 2004). So far, y-3 hordein (Hor v 21) from barley, Sec c 20 from rye, as well as Tri a 19 and Tri a 26 from wheat are included in the IUIS allergen list. 

Deamidation of proteins induces the conversion of glutamine and asparagine residues to acid groups, with the concomitant release of ammonia. Deamidation is known to be an important method for improving the functional properties of proteins, for instance, the increase in solubility of cereal prolamins,... 

Prolamines. Proteins insoluble in water, but dissolving in aqueous alcohol solutions. Found in the seeds of cereals. 

Cereal proteins when classified by the Osborne sequential extraction method yield four different classes albumins, which are water soluble, globulins, which are soluble in salt solutions, prolamins, which are soluble in alcohol-water mixtures, and glutelins, which are soluble in dilute acid or alkali. Chen and Bushuk added a fifth fraction by dividing the glutelin into two fractions, one soluble in dilute (0.05 m) acetic acid and the other insoluble in this reagent.5... 

These organelles occur in the endosperm of cereal grains and their structures are tissue specific. They are about 2-5 im in diameter and often contain globoid and occasionally crystalloid inclusions. Prolamin accumulates in small or large spherical bodies. Crystalline protein bodies are the sites of accumulation of nonprolamin storage proteins. 

Most of the applications of HPLC for protein analysis deal with the storage proteins in cereals (wheat, corn, rice, oat, barley) and beans (pea, soybeans). HPLC has proved useful for cultivar identihcation, protein separation, and characterization to detect adulterations (illegal addition of common wheat flour to durum wheat flour) [107]. Recently Losso et al. [146] have reported a rapid method for rice prolamin separation by perfusion chromatography on a RP POROS RH/2 column (UV detection at 230nm), sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE), and molecular size determination by MALDl-MS. DuPont et al. [147] used a combination of RP-HPLC and SDS-PAGE to determine the composition of wheat flour proteins previously fractionated by sequential extraction. 

WDEIA is a serious affection where symptoms are not only connected to wheat protein consumption, but they also appear after the introduction of wheat proteins into the digestive track, and following physical effort. Research on IgE of patients suffering from WDEIA showed that wheat gliadins are responsible for the disease, as well as corresponding taxonomic prolamines of closely related cereals (Varjonen et al., 1997). 

Shewry PR, Tatham AS. The prolamin storage proteins of cereal seeds Structure and evolution. Biochem J 1990 267 1-12. 

Gliadins are prolamins, a group of plant storage proteins with a high proline content, found in the seeds of cereal grains wheat (gliadin), barley (hordein), rye (secalin), corn (zein) and, as a minor protein, avenin in oats. 

Shewry, P.R. and Tatham, A.S. (1990). The prolamins storage proteins of cereal seeds— structure and evolution. Biochem. J., 267, 1-12. 

Nonwater (gluten) and alcohol-soluble (prolamin) fractions from cereal proteins... 

Shewry, PR., MUes, M.J., Tatham, A.S. (1994). The prolamin storage proteins of wheat and related cereals. Progress in Biophysics and Molecular Biology, 61, 37-59. 

Prolamins, a group of storage proteins occurring in cereals. They are soluble in 50-90% ethanol and can be so separated from the alcohol-insoluble glutelins. Prolamins are globular proteins (M, ... 

Cereal kernels contain about 70% carbohydrates and 8 to 17% proteins. About 80% of wheat proteins are gluten. Gluten from the cereals named previously is composed of prolamins (high in prohne and glutamine) and glutelins, which are storage proteins... 

Some cereal proteins are quite soluble in aqueous solution (albumins, globulins) but the functional proteins—prolamins and glutelins—are difficult to solubilize. This is important because, for example, we do not want wheat gluten proteins to be soluble in a dough system. However, in order to characterize proteins, it is usually necessary to have them in solution. Because the property of solubility is such an important one with respect to cereal proteins, we will dedicate this chapter to the topic. In keeping with the objectives of the book, we will attempt to approach the subject from the most general and fundamental basis. 

One of the questions posed in Chapter 1 was "Why does dough from cereals other than wheat not have viscoelastic properties " It is well established that the gluten proteins of wheat are responsible for the viscoelastic properties of wheat flom dough (see Chapter 6). The requirements for a protein (or any polymer) to exhibit viscoelasticity are discussed in Chapter 14. One of these is that the protein should be above its glass transition temperature (Tg). Zein, the prolamin protein of maize, is found to contribute viscoelastic properties to a zein-starch dough when the temperature is raised above its Tg at that water content (Bushuk and MacRitchie 1989 Lawton 1992). This shows that it is possible to obtain viscoelastic properties with nonwheat cereal proteins. 

Hamaker, B. R., A. A. Mohamed, J. E. Habben, C. P. Huang, and B. A. Larkins. 1995. Efficient procedures for extracting maize and sorghum kernel proteins reveals higher prolamin contents than the conventional method. Cereal Chemistry 72 583-588. 

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