Bacitracin

Lutein (purity > 90%), alcalase (enzyme activity > 200 U/mg), bile salts, and molecular weight standards including bacitracin, aprotinin, myohemoglobin, bovine serum albumin, and thyroglobulin were purchased from Shanghai Yuanye Biotechnology Co., Ltd. (Shanghai, China). Soybeans were bought from Fengyuan Zhongye Co., Ltd. (Lianyungang, China). Pepsin (enzyme activity > 2500 U/mg), trypsin (enzyme activity > 2500 U/mg), 8-aniline-1-naphthalensulfonic acid (ANS), and trinitrobenzenesulfonic acid (TNBS) were purchased from Sigma-Aldrich Co., (St. Louis, MO, USA). All other reagents and solvents were of at least analytical grade.

Defatted soy flour with low protein denaturation was obtained from Pingdingshan Jinjing Biological Technology Co., Ltd. (Zhengzhou, Henan, China). Alcalase (200 U mg⁻¹) was purchased from Shanghai Yuanye Biological Technology Co., Ltd. (Shanghai, China). C3G (purity ≥ 98%) was purchased from Nanjing Spring and Autumn Biotech Co., Ltd. (Nanjing, Jiangsu, China). 1-anilinonaphthalene-8-sulfonic acid (ANS) was obtained from Aladdin Co., Ltd. (Shanghai, China). 2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid) diammonium salt (ABTS) was obtained from Fluorochem Co., Ltd. (Hadfield, Derbyshire, UK), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) was obtained from Sigma-Aldrich (St. Louis, MO, USA). Molecular weight standards including cytochrome C, aprotinin, bacitracin, Gly−Gly−Tyr−Arg, Gly−Gly−Gly, carbonic anhydrase, bovine serum albumin, alcohol dehydrogenase, β-amylase and apoferritin were all purchased from Shanghai Yuanye Biological Technology Co., Ltd. (Shanghai, China). All other reagents were of analytical grade and were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China) unless otherwise noted.