周りにも予想外にグルテン不耐性の人々が多く、小ペプチドとして脳や小腸に作用するので体の不調を来たす。子供の場合はアトピーや小麦アレルギーで大変である。自閉症で悩む若い親御さんもいる。
パンうあ小麦製品は主食なので問題は厄介である。牛乳のカゼインやラクトース不耐性の問題を超えている。
作用は遅効性なので体に異常が出るまで大人でも気がつかない場合がある。
パンを作る時、塩と水で練ると粘々になるが、グルテンのお陰である。
しかしながら、今はグルテンフリーの時代でもある。グルテンやカゼインの作用で体調を悪くする人々が少なからず存在するのである。
品種改良で昔の小麦とは別物になったものと人類はどう向き合うべきか？
Abstract
Gluten proteins play a key role in determining the unique baking quality of wheat by conferring water absorption capacity, cohesivity, viscosity and elasticity on dough.
Gluten proteins can be divided into two main fractions according to their solubility in aqueous alcohols: the soluble gliadins and the insoluble glutenins.
Both fractions consist of numerous, partially closely related protein components characterized by high glutamine and proline contents.
Gliadins are mainly monomeric proteins with molecular weights (MWs) around 28,000-55,000 and can be classified according to their different primary structures into the alpha/beta-, gamma- and omega-type.
Disulphide bonds are either absent or present as intrachain crosslinks.
The glutenin fraction comprises aggregated proteins linked by interchain disulphide bonds; they have a varying size ranging from about 500,000 to more than 10 million.
After reduction of disulphide bonds, the resulting glutenin subunits show a solubility in aqueous alcohols similar to gliadins.
Based on primary structure, glutenin subunits have been divided into the high-molecular-weight (HMW) subunits (MW = 67,000-88,000) and low-molecular-weight (LMW) subunits (MW = 32,000-35,000).
Each gluten protein type consists or two or three different structural domains; one of them contains unique repetitive sequences rich in glutamine and proline.
Native glutenins are composed of a backbone formed by HMW subunit polymers and of LMW subunit polymers branched off from HMW subunits.
Non-covalent bonds such as hydrogen bonds, ionic bonds and hydrophobic bonds are important for the aggregation of gliadins and glutenins and implicate structure and physical properties of dough.
GLIADIN; 9007-90-3; 2-({1-[2-({1-[2-AMINO-3-(4-HYDROXYPHENYL)PROPANOYL]PYRROLIDIN-2-YL}FORMAMIDO)-4-CARBAMOYLBUTANOYL]PYRROLIDIN-2-YL}FORMAMIDO)-4-CARBAMOYLBUTANOIC ACID; ACMC-20d5l5; L-Glutamine,L-tyrosyl-L-prolyl-L-glutaminyl-L-prolyl- (9CI)
C29H41N7O9 631.687 g/mol pubchem.ncbi.nlm.nih.gov
文献３
ABSTRACT
The wheat gluten proteins correspond to the major storage proteins that are deposited in the starchy endosperm cells of the developing grain.
These form a continuous proteinaceous matrix in the cells of the mature dry grain and are brought together to form a continuous viscoelastic network when flour is mixed with water to form dough.
These viscoelastic properties underpin the utilization of wheat to give bread and other processed foods. One group of gluten proteins, the HMM subunits of glutenin, is particularly important in conferring high levels of elasticity (i.e. dough strength).
These proteins are present in HMM polymers that are stabilized by disulphide bonds and are considered to form the 'elastic backbone' of gluten.
However, the glutamine-rich repetitive sequences that comprise the central parts of the HMM subunits also form extensive arrays of interchain hydrogen bonds that may contribute to the elastic properties via a 'loop and train' mechanism.
Genetic engineering can be used to manipulate the amount and composition of the HMM subunits, leading to either increased dough strength or to more drastic changes in gluten structure and properties.
文献４
Abstract
Theterm gluten intolerance may refer to three types of human disorders: autoimmune celiac disease (CD), allergy to wheat and non-celiac gluten sensitivity (NCGS).
Gluten is a mixture of prolamin proteins present mostly in wheat, but also in barley, rye and oat.
Gluten can be subdivided into three major groups: S-rich, S-poor and high molecular weight proteins.
Prolamins within the groups possess similar structures and properties.
All gluten proteins are evolutionarily connected and share the same ancestral origin.
Gluten proteins are highly resistant to hydrolysis mediated by proteases of the human gastrointestinal tract. It results in emergence of pathogenic peptides, which cause CD and allergy in genetically predisposed people.
There is a hierarchy of peptide toxicity and peptide recognition by T cells.
Nowadays, there are several ways to detoxify gluten peptides: the most common is gluten-free diet (GFD), which has proved its effectiveness; prevention programs, enzymatic therapy, correction of gluten pathogenicity pathways and genetically modified grains with reduced immunotoxicity.
A deep understanding of gluten intolerance underlying mechanisms and detailed knowledge of gluten properties may lead to the emergence of novel effective approaches for treatment of gluten-related disorders.
図４－２ 3D reconstruction of DQ α^5-β^2-binding cleft with a deamidated α-gliadin peptide (green), using PyMOL (PBD ID 1S9V)
Keywords: gluten, celiac disease, NCGS, wheat allergy, gluten intolerance, gliadin, glutenin, hordein, secalin, avenin
Conclusions
Nowadays, gluten intolerance is an important issue.
The number of people diagnosed with gluten intolerance is increasing.
Thus, there is a need for more effective and novel approaches to treat gluten-related disorders. Externally, it is caused by the consumption of gluten prolamin proteins present in wheat, barley and rye.
In the present paper, we have summarized the knowledge on the classification, properties, structure, evolution and role of gluten proteins in the pathogenesis of gluten intolerance manifestations.
Even though gluten proteins—gliadins, glutenins, hordeins, secalins and avenins—share similar features and evolutional origins, they possess different pathogenicities.
A detailed understanding of the principal properties of gluten intolerance causative agents open ups the possibilities for the development of novel therapeutic approaches such as with improved low pathogenic wheat, barley and rye plant lines; renewed therapeutic enzymatic drugs and vaccines.
This will obviate the need for GFD and improve the quality of life of people suffering from gluten intolerance.