Development of a Large-Scale (50 L) Apparatus for Ampholyte-free Isoelectric Focusing (Autofocusing) of Peptides in Enzymatic Hydrolysates of Food Proteins

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• 作者：Kaori Hashimoto ; Kenji Sato ; Yasushi Nakamura ; and Kozo Ohtsuki
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2005
• 出版时间：May 18, 2005
• 年：2005
• 卷：53
• 期：10
• 页码：3801 - 3806
• 全文大小：305K
• 年卷期：v.53,no.10(May 18, 2005)
• ISSN：1520-5118

文摘

It has been demonstrated that peptides in enzymatic hydrolysates of proteins can be fractionated onthe basis of the amphoteric nature of the sample peptides, by a laboratory-scale isoelectric focusingapparatus, without adding a chemically synthesized carrier ampholyte. This approach is referred toas autofocusing. In the present study, a large-scale (up to 50 L) autofocusing apparatus was developedand tested. A tank (125 cm × 25 cm × 20 cm) was divided into 12 compartments by 11 plates, eachwith a window covered in a thin agarose gel layer supported by a nylon screen (100 mesh). Thecompartments at both ends were filled with 0.1 N phosphoric acid (anode) and 0.1 N NaOH (cathode),respectively, functioning as electrode compartments. The remaining compartments were used forsample compartments. Autofocusing was carried out at constant voltage according to two differentmethods. In method 1, all sample compartments were filled with a 1% water solution of casein ormilk whey protein hydrolysates. In method 2, two compartments located in the center of the tankwere filled with 5% sample solution and the others were filled with deionized water. Compositionaland sequence analyses of the autofocusing fractions revealed that peptides in the two hydrolysatescan be fractionated within 24 h by the present apparatus. Better fractionation was obtained by method2, whereas enrichment of some peptides occurred by using method 1.Keywords: Autofocusing; peptide fractionation; preparative isoelectric focusing; electrophoresis;functional foods; peptide; food