Oxidation-Induced Unfolding Facilitates Myosin Cross-Linking in Myofibrillar Protein By Microbial Transglutaminase.

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Oxidation-Induced Unfolding Facilitates Myosin Cross-Linking in Myofibrillar Protein By Microbial Transglutaminase.

J Agric Food Chem. 2012 Jul 18;

Authors: Li C, Xiong YL, Chen J

Abstract
Myofibrillar protein from pork Longissimus muscle was oxidatively stressed for 2 and 24 h at 4 �C with mixed 10 ?? FeCl3/100 ?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 �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 (19.8-27.6%) at 1 mM H2O2 occurred compared to 11.6% in non-oxidized samples (P < 0.05) after MTG treatment. This coincided with more pronounced losses of myosin in oxidized samples (up to 33.2%) compared to 21.1% in non-oxidized (P < 0.05), which was attributed to lysine-glutamine cross-linking as suggested by SDS-PAGE.

PMID: 22809283 [PubMed - as supplied by publisher]

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