Oxidation-Induced Unfolding Facilitates Myosin Cross-Linking in Myofibrillar Protein by Microbial Transglutaminase
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- 作者：Chunqiang Li ; Youling L. Xiong ; Jie Chen
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2012
- 出版时间：August 15, 2012
- 年：2012
- 卷：60
- 期：32
- 页码：8020-8027
- 全文大小：407K
- 年卷期：v.60,no.32(August 15, 2012)
- ISSN：1520-5118
文摘
Myofibrillar protein from pork Longissimus muscle was oxidatively stressed for 2 and 24 h at 4 掳C with mixed 10 渭M FeCl3/100 渭M ascorbic acid/1, 5, or 10 mM H2O2 (which produces hydroxyl radicals) and then treated with microbial transglutaminase (MTG) (E:S = 1:20) for 2 h at 4 掳C. Oxidation induced significant protein structural changes (P < 0.05) as evidenced by suppressed K-ATPase activity, elevated Ca-ATPase activity, increased carbonyl and disulfide contents, and reduced conformational stability, all in a H2O2 dose-dependent manner. The structural alterations, notably with mild oxidation, led to stronger MTG catalysis. More substantial amine reductions (19.8鈥?7.6%) at 1 mM H2O2 occurred as compared to 11.6% in nonoxidized samples (P < 0.05) after MTG treatment. This coincided with more pronounced losses of myosin in oxidized samples (up to 33.2%) as compared to 21.1% in nonoxidized (P < 0.05), which was attributed to glutamine鈥搇ysine cross-linking as suggested by sodium dodecyl sulfate鈥損olyacrylamide gel electrophoresis.