Wheat glutenin

Fig. 10. Backscattered Raman and ROA spectra in H2O of wheat glutenin T-A-l peptide (top pair) at pH 3.5, wheat A-gliadin (middle pair) at pH 3.5, and wheat ogliadin (bottom pair) at pH 2.6. 

Fig. 7.6. Figure 7.6. Backscattered ICP Raman (IR f IL) ancj j oA (IR - IL) spectra of (a) human lysozyme in the native state, (b) human lysozyme in the low pH molten globule state, and (c) the T-A-l peptide from wheat glutenin. Adapted from references 45 and 46...

Luo, C., Branlard, G., Griffin, W.B., McNeil, D.L. 2000. The effect of nitrogen and sulphur fertilization and their interaction with genotype on wheat glutenins and quality parameters. J Cereal Sci 31 185-194. 

Shewry, P.R., Halford, N.G., Tatham, A.S., Popineau, Y., Lafiandra, D., and Belton, P.S. (2003). The high molecular weight subunits of wheat glutenin and their role in determining wheat processing properties. Adv. Food Sci. Nutrition 45 219-302. 

Fig. 1. Expansion of the aliphatic region of the TOCSY HR-MAS spectrum of alkylated subunit 1Dx5 hydrated with excess of D20. Spinning at 8 kHz. The cross-peaks of the two glutamine residues are indicated in the spectrum. Reprinted from Biopolymers, Vol. 58(1), E. Alberti, E. Humpfer, M. Spraul, S. M. Gilbert, A. S. Tatham, P. R. Shewry and A. M. Gil, A high resolution H MAS NMR study of a high-Mr subunit of wheat glutenin , pp. 33-45, Copyright 2001, with permission from John Wiley Sons, Inc.

Several models for the structure of wheat glutenin have been proposed. One of the earliest molecular models was that of Ewart [62]. He subsequently modified the model. Ewart s latest model shows one disulfide bond between two adjacent polypeptide chains of glutenins, which consist of linear polymers. Ewart pointed out that the rheological properties of dough are dependent on the presence of theologically active disulfide bonds and thiol groups as well as on secondary forces in the concatenations [63]. 

Payne, P.I., Holt, L.M., and Law, C.N. Structural and genetic studies on the high-molecular-weight subunits of wheat glutenins. Part I. Allelic variation in subunits amongst varieties of wheat (Triticum aestivum). Theor. Appl. Genet. 60 229-236, 1981. 

Feeney, K.A., WeUner, N., Gilbert, S.M. et al. (2(X)3) Molecular structures and interactions of repetitive peptides based on wheat glutenin subunits depend on chain length. Biopolymers, 72, 123-131. 

Burnouf and Bietz [19] first explored methods for solubilization, stabilization, and RP-HPLC analysis of wheat glutenin. For optimal separations, glutenin was extracted with solutions containing 8M urea or 6M guanidine hydrochloride and 5% 2-mercaptoethanol or 0.1% DTT resulting thiol groups were stabilized by alkylation with 4-vinylpyridine acidified reaction mixtures could then be analyzed directly by RP-HPLC. 

Extraction of Unreduced Glutelins. Protein molecular sizes or size distributions often influence functional properties, necessitating extraction and characterization of native proteins. Various procedures have solubilized and fractionated unreduced wheat glutenin using dilute acetic acid [34], solutions differing in HCl concentration [35-37], or 50% and 70% I-propanol [38]. 

A more subtle problem is presented by proteins that associate or polymerize, noncovalently or covalently, but remain soluble. One example for zein was noted before (Fig. 5) a broad envelope underneath well-resolved peaks may suggest association or polymerization. Similarly, Huebner and Bietz [22] showed that medium-MW oligomeric wheat glutenin molecules eluted upon RP- HPLC as a broad peak but resolved as sharp peaks after disulfide bond cleavage. 

Figure 9 RP-HPLC separations of wheat glutenin subunits (cv. Apollo) insoluble (left) and soluble (right) in 70% ethanol— dithioerythritol. (From Ref. 32.)...

Figure 11.5 Effect of water content on the Tg and minimum thermosetting temperature (TJ for wheat gluten proteins [163]. Hoseney and co-workers [163] (0), Kalichevski and co-workers [164] ( ), Nicholls and co-workers (O), Cherian and Chinachoti [154] (A), and Pouplin and co-workers [187] (X) the thermosetting temperature ( ) was determined for wheat glutenins [166]...

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