A proposed nomenclature for the alcohol-soluble proteins (zeins) of maize (Zea mays L.)

To improve the rheological properties of zein doughs, α-type zein and zein-starch doughs were prepared with the oxidising agents, hydrogen peroxide and peroxidase, which strengthen gluten-based doughs by cross-linking. Hydrogen peroxide and peroxidase increased zein dough extensibility compared to preparation with water. Hydrogen peroxide prepared zein doughs were extensible and cohesive below zein's glass transition temperature.The doughs did not exude water and maintained flexibility when stored. Confocal laser scanning microscopy revealed that in zein-starch doughs prepared with hydrogen peroxide a thin continuous zein matrix was formed around the starch granules, whereas doughs prepared with water exhibited clumps of granules. SDS-PAGE of zein doughs and films treated with the oxidising agents showed no evidence of zein polymerisation, nor did Fourier transform infrared spectrometry reveal any significant changes in secondary structure. Further, hydrogen peroxide treatment did not increase zein film glass transition temperature, but it did increase transition enthalpy, and film water uptake increased with hydrogen peroxide concentration. The greatly increased extensibility of hydrogen peroxide prepared zein doughs and their improved water-holding are not due to oxidative cross-linking. It is proposed that the effects are primarily due to hydroxylation of amino acid aliphatic side chains, improving hydration through hydrogen bonding.2

show abstract

“…bands less than or greater than those of α-zein (Esen, 1987) (M r 21-25 kDa) (Fig. 2S, supplementary material).…”

Section: Zein Dough and Film Physico-chemical Propertiesmentioning

confidence: 99%

Oxidation of commercial (α-type) zein with hydrogen peroxide improves its hydration and dramatically increases dough extensibility even below its glass transition temperature

Taylor

Johnson

Taylor

et al. 2016

Journal of Cereal Science

View full text Add to dashboard Cite

show abstract

“…Kernel texture is determined by the relative amounts of hard (vitreous) and soft (opaque) endosperm and there is a positive correlation between zein storage proteins and kernel vitreousness (1). Zeins are a heterogeneous mixture of alcohol-soluble proteins, falling into four classes based on their structure (α-, β-, γ-, and δ-zeins) (2). The zeins extracted with the Osborne method (3) are classified as z1 (19-and 22-kDa α-zeins) and the cross-linked z2 group (50-, 27-, and 16-kDa γ-zeins, 15-kDa β-zein, and 18-and 10-kDa δ-zeins) (4,5).…”

mentioning

confidence: 99%

γ-Zeins are essential for endosperm modification in quality protein maize

Holding

Messing

2010

Proc. Natl. Acad. Sci. U.S.A.

130

117

View full text Add to dashboard Cite

Essential amino acids like lysine and tryptophan are deficient in corn meal because of the abundance of zein storage proteins that lack these amino acids. A natural mutant, opaque 2 (o2) causes reduction of zeins, an increase of nonzein proteins, and as a consequence, a doubling of lysine levels. However, o2's soft inferior kernels precluded its commercial use. Breeders subsequently overcame kernel softness, selecting several quantitative loci (QTLs), called o2 modifiers, without losing the high-lysine trait. These maize lines are known as "quality protein maize" (QPM). One of the QTLs is linked to the 27-kDa γ-zein locus on chromosome 7S. Moreover, QPM lines have 2-to 3-fold higher levels of the 27-kDa γ-zein, but the physiological significance of this increase is not known. Because the 27-and 16-kDa γ-zein genes are highly conserved in DNA sequence, we introduced a dominant RNAi transgene into a QPM line (CM105Mo2) to eliminate expression of them both. Elimination of γ-zeins disrupts endosperm modification by o2 modifiers, indicating their hypostatic action to γ-zeins. Abnormalities in protein body structure and their interaction with starch granules in the F1 with Mo2/+; o2/o2; γRNAi/+ genotype suggests that γ-zeins are essential for restoring protein body density and starch grain interaction in QPM. To eliminate pleiotropic effects caused by o2, the 22-kDa α-zein, γ-zein, and β-zein RNAis were stacked, resulting in protein bodies forming as honeycomb-like structures. We are unique in presenting clear demonstration that γ-zeins play a mechanistic role in QPM, providing a previously unexplored rationale for molecular breeding.electron microscopy | stacking of RNAi events | storage organs | opaque phenotype | kernel hardness G rain hardness is a key agronomic trait in maize (Zea mays L.)because it provides resistance to damage during harvesting and marketing, as well as to insect and fungal damage. Kernel texture is determined by the relative amounts of hard (vitreous) and soft (opaque) endosperm and there is a positive correlation between zein storage proteins and kernel vitreousness (1). Zeins are a heterogeneous mixture of alcohol-soluble proteins, falling into four classes based on their structure (α-, β-, γ-, and δ-zeins) (2). The zeins extracted with the Osborne method (3) are classified as z1 (19-and 22-kDa α-zeins) and the cross-linked z2 group (50-, 27-, and 16-kDa γ-zeins, 15-kDa β-zein, and 18-and 10-kDa δ-zeins) (4, 5). Zeins are deposited in rough endoplasmic reticulum-delimited protein bodies (PBs) in endosperm cells from around 10 d after pollination (DAP) (6, 7). Alpha-and δ-zeins are mainly stored in the center of PBs, and γ-and β-zeins are deposited in the peripheral region (8). The Cys-rich γ-and β-zeins have redundant function in the stabilization of PB morphology (9). The translucency (vitreousness) of the mature kernel is influenced by PB composition and the spatial organization of α-, β-, γ-, and δ-zeins (10-16).Because zeins are essentially devoid of lysine and tryptophan, their high-lev...

show abstract

“…При разделении в полиакриламидном геле α-, β-, γ-и δ-классы зеинов рас-падаются на субфракции, различающиеся по электрофоретической подвиж-ности и молекулярной массе (Esen, 1987). Полиморфизм электрофоретических спектров зеинов связан как с отсутствием одного или нескольких компонентов спектра, так и с вариабельностью в интенсивности окрашивания фракций в геле.…”

Section: результаты и обсуждениеunclassified

Marker-assisted identification of maize genotypes with improved protein quality

Орловская¹,

Кубрак²,

Вакула³

et al. 2015

Vestn. VOGiS

View full text Add to dashboard Cite

currently�� more than �0 % of maize is used for food and fodder; therefore�� grain quality im�rovement can increase its nutritive and energy value. Deficiency of two essential amino acids (lysine and try�to�han� significantly reduces the nutritional quality of maize �roteins. However�� in com�arison to conventional maize varieties�� opaque2 (o2� mutants have greater contents of lysine and try�to�han in their endos�erm �roteins and their bioavailability is better. The aim of the study was identification of maize accessions with high-quality �rotein. a collection of maize accessions of various ecogeogra�hical origins was studied by molecular methods. This a��roach was ex�ected to im�rove maize breeding efficiency. we collected 54 maize genoty�es differing in grain quality �erformance. am�lification with three s�ecific mar�ers to the opaque-2 gene (�hi05�� hi112 and umc1066� revealed homozygous recessive o2 genoty�es�� associated with im�roved nutritional quality of the �rotein. UrEa-PaG electro�horesis of zein �roteins was used for Quality Protein Maize (QPM� identification. in addition to the mutant o2 allele�� QPM contains genetic modifiers that convert starchy endos�erm of o2 mutant to the hard vitreous �henoty�e. The selected QPM accessions are of interest for maize breeding �rograms aimed at grain quality im�rovement. The use of the mar�ers to o2 and modifier genes accelerates the develo�ment of QPM varieties and significantly reduces the labor and financial costs of their �roduction.Key words�� maize; QPM genoty�e; SSr mar�ers; UrEaPaGE; zeins.В настоящее время �олее �0 % кукурузы испол��зуется для производства пищевых продуктов и кормов�� поэтому улу�шение ка�ественных показателей зерна может повысит�� пищеву� и энергети�еску� ценност�� данной кул��туры. Дефицит двух незаменимых аминокислот�� лизина и триптофана�� существенно снижает питател��ное ка�ество �елка кукурузы. Однако мутанты кукурузы opaque2 (o2� име�т увели�енное содержание лизина и триптофана в �елке эндосперма по сравнени� с традиционными сортами�� то повышает �иологи�еску� ценност�� кукурузного �елка. Цел�� исследования -выявление о�разцов с высоким ка�еством �елка в коллекции кукурузы разли�ного эколого-географи�еского происхождения с испол��зованием молекулярно-генети�еских методов для повышения эффективности селекции данной кул��туры. Создана коллекция из 54 генотипов кукурузы с разли�ными ка�ественными показателями зерна. С помощ�� трех специфи�еских маркеров к гену оpaque-2 (�hi 05�� hi 112 и umc 1066� выявлены генотипы кукурузы�� гомозиготные по рецессивному аллел� o2�� который связан с улу�шенными питател��ными свойствами �елка. Электрофорети�еский анализ зеинов позволил ото�рат�� о�разцы Quality Protein Maize (QPM�� которые содержат наряду с мутантным аллелем о2 генети�еские модификаторы�� прео�разу�щие крахмал��ный эндосперм o2-мутанта в твердый�� стекловидный фенотип. Выделенные в резул��тате исследования QPM-о�разцы представля�т интерес для селекционных программ кукурузы�� направленных на повышение ка�ества зерна. �рименение...

show abstract

A proposed nomenclature for the alcohol-soluble proteins (zeins) of maize (Zea mays L.)

Cited by 215 publications

References 10 publications

Oxidation of commercial (α-type) zein with hydrogen peroxide improves its hydration and dramatically increases dough extensibility even below its glass transition temperature

Oxidation of commercial (α-type) zein with hydrogen peroxide improves its hydration and dramatically increases dough extensibility even below its glass transition temperature

γ-Zeins are essential for endosperm modification in quality protein maize

Marker-assisted identification of maize genotypes with improved protein quality

Contact Info

Product

Resources

About