Department of Bio-molecular Engineering, Kyoto Institute of Technology , Matsugasaki, Sakyo, Kyoto 606-8585, Japan.
J Agric Food Chem. 2013 Sep 11;61(36):8668-75. doi: 10.1021/jf402456v. Epub 2013 Aug 28.
Ovalbumin (OVA), a major globular protein in egg white, forms semiflexible fibrillar aggregates during heat-induced gelation. The N-terminal amphiphilic region (pN1-22) of OVA is removed after treatment with pepsin at pH 4 to leave a large OVA fragment (pOVA). The conformation and thermal stability of pOVA and OVA are similar, but the rheological strength of the heat-induced gel of pOVA is much lower compared to that of OVA. The aggregation rate of pOVA, which forms spherical aggregates, was lower than that of OVA. These results suggest that the N-terminal amphiphilic region of OVA facilitates the α-to-β conformational transition, which triggers OVA fibril formation. Heat treatment of OVA in the presence of pN1-22 consistently resulted in the formation of straight fibrils. The strength of OVA and collagen gels was increased when prepared in the presence of pN1-22, suggesting that pN1-22 may be used to control the properties of protein gels.
卵清蛋白（OVA）是蛋清中的一种主要球状蛋白，在热诱导凝胶化过程中形成半柔性纤维状聚集物。用胃蛋白酶在 pH 4 下处理后，OVA 的 N 端两亲性区域（pN1-22）被去除，留下一个大的 OVA 片段（pOVA）。pOVA 和 OVA 的构象和热稳定性相似，但与 OVA 相比，pOVA 热诱导凝胶的流变强度要低得多。形成球形聚集物的 pOVA 的聚集速率低于 OVA。这些结果表明，OVA 的 N 端两亲性区域促进了 α 到 β 的构象转变，从而引发了 OVA 纤维的形成。在存在 pN1-22 的情况下对 OVA 进行热处理，始终会导致直纤维的形成。在存在 pN1-22 的情况下制备 OVA 和胶原蛋白凝胶时，其强度增加，这表明 pN1-22 可用于控制蛋白质凝胶的性质。
