Glutenin

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HMW Glutenin
Identifiers
SymbolGlutenin
Pfam PF03157
InterPro IPR001419

Glutenin (a type of glutelin) is a major protein within wheat flour, making up 47% of the total protein content. The glutenins are protein aggregates of high-molecular-mass (HMW) and low-molecular-mass (LMW) subunits with molar masses from about 200,000 to a few million, which are stabilized by intermolecular disulfide bonds, hydrophobic interactions and other forces. Glutenin is responsible for the strength and elasticity of dough. [1]

Wheat gluten proteins consist of two major fractions: the gliadins and the glutenins. Gliadins are monomeric proteins, which can be separated into four groups: alpha-, beta-, gamma- and omega-gliadins. They are structurally similar to LMW glutenins. Glutenins occur as multimeric aggregates of high-molecular-mass and low-molecular-mass subunits held together by disulfide bonds.[ citation needed ] The way the glutenins form their disulfide bond network is predicted to be regulated by the hydrophobicity in the peptide sections where their cysteins are located, explaining why the gliadins are monomeric despite sharing similar conserved cysteine motifs as the LMW-glutenins. [2]

Breadmaking qualities are largely dependent on the number and composition of HMW glutenin subunits. It has been demonstrated that alleles Glu-A1b (Ax2∗) and Glu-D1d (Dx5 + Dy10) are normally associated with superior end-use quality, especially dough strength.[ citation needed ]

Related Research Articles

Gluten Group of cereal grain proteins

Gluten is a structural protein naturally found in certain cereal grains. Although, particularly, "gluten" pertains only to wheat proteins, in medical literature it refers to the combination of prolamin and glutelin proteins naturally occurring in all grains that have been proved to be capable of triggering celiac disease. These include any species of wheat, barley, rye and some oat cultivars, as well as any cross hybrids of these grains. Gluten makes up 75–85% of the total protein in bread wheat.

Bread Food made of flour and water

Bread is a staple food prepared from a dough of flour and water, usually by baking. Throughout recorded history and around the world, it has been an important part of many cultures' diet. It is one of the oldest human-made foods, having been of significance since the dawn of agriculture, and plays an essential role in both religious rituals and secular culture.

Protein folding Change of a linear protein chain to a 3D structure

Protein folding is the physical process by which a protein chain is translated to its native three-dimensional structure, typically a "folded" conformation by which the protein becomes biologically functional. Via an expeditious and reproducible process, a polypeptide folds into its characteristic three-dimensional structure from a random coil. Each protein exists first as an unfolded polypeptide or random coil after being translated from a sequence of mRNA to a linear chain of amino acids. At this stage the polypeptide lacks any stable (long-lasting) three-dimensional structure. As the polypeptide chain is being synthesized by a ribosome, the linear chain begins to fold into its three-dimensional structure.

In biochemistry, a disulfide refers to a functional group with the structure R−S−S−R′. The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In biology, disulfide bridges formed between thiol groups in two cysteine residues are an important component of the secondary and tertiary structure of proteins. Persulfide usually refers to R−S−S−H compounds.

Croissant French pastry

A croissant is a buttery, flaky, French viennoiserie pastry inspired by the shape of the Austrian kipferl but using the French yeast-leavened laminated dough. Croissants are named for their historical crescent shape, the dough is layered with butter, rolled and folded several times in succession, then rolled into a thin sheet, in a technique called laminating. The process results in a layered, flaky texture, similar to a puff pastry.

Spelt Species of grain

Spelt, also known as dinkel wheat or hulled wheat, is a species of wheat that has been cultivated since approximately 5000 BC.

Protein structure Three-dimensional arrangement of atoms in an amino acid-chain molecule

Protein structure is the three-dimensional arrangement of atoms in an amino acid-chain molecule. Proteins are polymers – specifically polypeptides – formed from sequences of amino acids, the monomers of the polymer. A single amino acid monomer may also be called a residue indicating a repeating unit of a polymer. Proteins form by amino acids undergoing condensation reactions, in which the amino acids lose one water molecule per reaction in order to attach to one another with a peptide bond. By convention, a chain under 30 amino acids is often identified as a peptide, rather than a protein. To be able to perform their biological function, proteins fold into one or more specific spatial conformations driven by a number of non-covalent interactions such as hydrogen bonding, ionic interactions, Van der Waals forces, and hydrophobic packing. To understand the functions of proteins at a molecular level, it is often necessary to determine their three-dimensional structure. This is the topic of the scientific field of structural biology, which employs techniques such as X-ray crystallography, NMR spectroscopy, cryo electron microscopy (cryo-EM) and dual polarisation interferometry to determine the structure of proteins.

Gliadin

Gliadin is a class of proteins present in wheat and several other cereals within the grass genus Triticum. Gliadins, which are a component of gluten, are essential for giving bread the ability to rise properly during baking. Gliadins and glutenins are the two main components of the gluten fraction of the wheat seed. This gluten is found in products such as wheat flour. Gluten is split about evenly between the gliadins and glutenins, although there are variations found in different sources.

A non-covalent interaction differs from a covalent bond in that it does not involve the sharing of electrons, but rather involves more dispersed variations of electromagnetic interactions between molecules or within a molecule. The chemical energy released in the formation of non-covalent interactions is typically on the order of 1–5 kcal/mol (1000–5000 calories per 6.02 × 1023 molecules). Non-covalent interactions can be classified into different categories, such as electrostatic, π-effects, van der Waals forces, and hydrophobic effects.

Kneading Process of preparing dough

In cooking, kneading is a process in the making of bread or dough, used to mix the ingredients and add strength to the final product. Its importance lies in the mixing of flour with water; when these two ingredients are combined and kneaded, the gliadin and glutenin proteins in the flour expand and form strands of gluten, which gives bread its texture. The kneading process warms and stretches these gluten strands, eventually creating a springy and elastic dough. If bread dough is not kneaded enough, it will not be able to hold the tiny pockets of gas created by the leavening agent, and will collapse, leaving a heavy and dense loaf.

Thermostability

Thermostability is the quality of a substance to resist irreversible change in its chemical or physical structure, often by resisting decomposition or polymerization, at a high relative temperature.

Prolamins are a group of plant storage proteins having a high proline amino acid content. They are found in plants, mainly in the seeds of cereal grains such as wheat (gliadin), barley (hordein), rye (secalin), corn (zein), sorghum (kafirin), and oats (avenin). They are characterised by a high glutamine and proline content, and have poor solubility in water. They solubilise best in strong alcohol [70-80%], light acid, and alkaline solutions. The prolamins of the tribe Triticeae, such as wheat gliadin, and related proteins are known to trigger coeliac disease, an autoimmune condition, in genetically predisposed individuals.

Wheat allergy Medical condition

Wheat allergy is an allergy to wheat which typically presents itself as a food allergy, but can also be a contact allergy resulting from occupational exposure. Like all allergies, wheat allergy involves immunoglobulin E and mast cell response. Typically the allergy is limited to the seed storage proteins of wheat. Some reactions are restricted to wheat proteins, while others can react across many varieties of seeds and other plant tissues. Wheat allergy is rare. Prevalence in adults was found to be 0.21% in a 2012 study in Japan.

Triticeae glutens Seed storage protein in mature wheat seeds

Gluten is the seed storage protein in mature wheat seeds. It is the sticky substance in bread wheat which allows dough to rise and retain its shape during baking. The same, or very similar, proteins are also found in related grasses within the tribe Triticeae. Seed glutens of some non-Triticeae plants have similar properties, but none can perform on a par with those of the Triticeae taxa, particularly the Triticum species. What distinguishes bread wheat from these other grass seeds is the quantity of these proteins and the level of subcomponents, with bread wheat having the highest protein content and a complex mixture of proteins derived from three grass species.

Glutelins are a class of prolamin proteins found in the endosperm of certain seeds of the grass family. They constitute a major component of the protein composite collectively referred to as gluten. Glutenin is the most common glutelin, as it is found in wheat and is responsible for some of the refined baking properties in bread wheat. The 2glutelins of barley and ryeis have also been identified. Glutelins are the primary form of energy storage in the endosperm of rice grains.

<i>Elymus canadensis</i> Species of grass

Elymus canadensis, commonly known as Canada wild rye or Canadian wildrye, is a species of wild rye native to much of North America. It is most abundant in the central plains and Great Plains. It grows in a number of ecosystems, including woodlands, savannas, dunes, and prairies, sometimes in areas that have been disturbed.

The immunochemistry of Triticeae glutens is important in several inflammatory diseases. It can be subdivided into innate responses, class II mediated presentation, class I mediated stimulation of killer cells, and antibody recognition. The responses to gluten proteins and polypeptide regions differs according to the type of gluten sensitivity. The response is also dependent on the genetic makeup of the human leukocyte antigen genes. In gluten sensitive enteropathy, there are 4 types of recognition, innate immunity, HLA-DQ, and antibody recognition of gliadin and transglutaminase. With idiopathic gluten sensitivity only antibody recognition to gliadin has been resolved. In wheat allergy, the response pathways are mediated through IgE against other wheat proteins and other forms of gliadin.

Food physical chemistry is considered to be a branch of Food chemistry concerned with the study of both physical and chemical interactions in foods in terms of physical and chemical principles applied to food systems, as well as the applications of physical/chemical techniques and instrumentation for the study of foods. This field encompasses the "physiochemical principles of the reactions and conversions that occur during the manufacture, handling, and storage of foods"

<i>Psathyrostachys juncea</i> Species of grass

Psathyrostachys juncea is a species of grass known by the common name Russian wildrye. It was formerly classified as Elymus junceus. It is native to Russia and China, and has been introduced to other parts of the world, such as Canada and the United States. Psathyrostachys juncea is a great source of food for grazing animals, as it has high nutrition value in its dense basal leaves, even in the late summer and autumn seasons. This species can grow and prosper in many harsh environments, making it an ideal candidate for improvement as it can grow in areas were farming is difficult. This species is a drought-resistant forage plant and can survive during the cool seasons. It is also a cross-pollinator and is self-sterile. This means that P. juncea cannot self-fertilize; it must find another plant of the same species with which to exchange gametes. Self-sterilization increases the genetic diversity of a species.

Irditoxin

Irditoxin is a three-finger toxin (3FTx) protein found in the venom of the brown tree snake and likely in other members of the genus Boiga. It is a heterodimer composed of two distinct protein chains, each of the three-finger protein fold, linked by an intermolecular disulfide bond. This structure is unusual for 3FTx proteins, which are most commonly monomeric.

References

  1. Belitz HD, Grosch W, Schieberle P (2004). Food Chemistry (3rd ed.). Springer. ISBN   978-3-540-64704-1.
  2. Markgren J, Hedenqvist M, Rasheed F, Skepö M, Johansson E (July 2020). "Glutenin and Gliadin, a Piece in the Puzzle of their Structural Properties in the Cell Described through Monte Carlo Simulations". Biomolecules. 10 (8): 1095. doi: 10.3390/biom10081095 . PMID   32717949. S2CID   220841839.