Cereals & Grains Association
Log In

Use of SDS to Extract Sorghum and Maize Proteins for Free Zone Capillary Electrophoresis (FZCE) Analysis1

January 2001 Volume 78 Number 1
Pages 84 — 87
S. R. Bean , 2 C. Hicks , 3 M. Tuinstra , 3 and G. L. Lookhart 4

Cooperative investigations, United States Department of Agriculture-Agricultural Research Service (USDA-ARS) and the Departments of Agronomy and Grain Science and Industry, Kansas State University. Contribution 00-426-J, Kansas State Agricultural Experiment Station, Manhattan 66506. Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by the USDA implies no approval of the product to the exclusion of others that may also be suitable. Dept. Grain Science and Industry, Kansas State University, Manhattan KS 66506. Dept. Agronomy, Kansas State University. Corresponding author. USDA-ARS, Grain Marketing and Production Research Center and Kansas State University, Manhattan 66502. Phone: (785) 776-2376; Fax: (785) 776-2792; E-mail: george@usgmrl.ksu.edu


Go to Article:
http://dx.doi.org/10.1094/CCHEM.2001.78.1.84
Accepted October 5, 2000.
ABSTRACT

Two different extraction methods for extracting sorghum (Sorghum bicolor L. Moench.) storage proteins for free zone capillary electrophoresis (FZCE) analysis were compared. A traditional solvent based on 60% t-butanol was compared with a pH 10 borate buffer containing the anionic detergent SDS followed by precipitation of nonkafirins using 60% t-butanol. FZCE analysis of both types of extracts showed identical patterns, despite the fact that the SDS should have given all proteins equal charge-to-mass ratios. This methodology was also successfully applied to maize proteins. The use of t-butanol to precipitate nonkafirins, combined with electrophoresis at low pH, is thought to have removed the SDS from the storage proteins. The SDS extraction procedure produced more stable extracts for FZCE analysis. These extracts could also be used directly for SDS capillary electrophoresis (SDS-CE) separations. Kafirins from 15 genotypes were extracted with this procedure and analyzed by FZCE and SDS-CE. Resolution of the kafirins by FZCE was much higher than the SDS-CE, demonstrating that the kafirin proteins possessed a high level of charge density variability within a relatively small molecular size distribution. Two distinct groups of α-kafirins could be seen in the FZCE electropherograms.


This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. American Association of Cereal Chemists, Inc., 2001.