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Title: VARIATION AMONG HIGH MOLECULAR WEIGHT SUBUNITS OF GLUTENIN DETECTED BY CAPILLARY ELECTROPHORESIS

Author
item SUTTON, KEVIN - N ZEALAND INST CROP & FD
item Bietz, Jerold

Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Glutenin is part of the elastic protein gluten which allows bread to be made. Glutenin is a polymer. Its largest subunits, which differ among wheats, affect wheat quality. It is important, therefore, to be able to identify and measure these subunits. A new technique, capillary electrophoresis, is useful for this purpose. By modifying the way in which hglutenin is isolated and the way that it is analyzed by capillary electrophoresis, large glutenin subunits of all wheats can be quickly and accurately measured. Results from this method are often better than analytical results from other methods. This new method for analyzing glutenin's large subunits can be useful during wheat breeding to identify and select high-quality lines.

Technical Abstract: Capillary electrophoresis (CE), in conjunction with a selective precipitation procedure, was used to reveal biochemical variation among Glu-D1 high-molecular weight (HMW) glutenin subunits in wheat cultivars. The heterogeneity observed paralleled that previously recognized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), although some differences in relative mobility of protein bands were observed. Modifications of the CE method introduced in this paper allow the resolution of all HMW-glutenin subunits commonly found in wheat cultivars worldwide. When the results presented in this paper are compared to those currently in the literature, the inclusion of the precipitation step in the preparation of the HMW-glutenin subunits appears to give cleaner samples, with fewer interfering gliadin and low-molecular weight glutenin subunits, for CE analysis. The technique could be used, in conjunction with SDS-PAGE and/or reversed-phase high-performance liquid chromatography (RP-HPLC), in breeding programmes to confirm the HMW-glutenin subunit composition of parents and promising selections and/or to establish the presence of "unusual" HMW-glutenin subunits. Quantitative analysis was carried out of glutenin subunits from New Zealand cultivars Otane, which is of good breadmaking quality, and Karamu, which is of poor breadmaking quality. Otane had greater relative concentrations of HMW-glutenin subunits than did Karamu, closely paralleling results previously obtained for these cultivars using RP-HPLC.