期刊
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
卷 59, 期 5, 页码 1837-1846出版社
AMER CHEMICAL SOC
DOI: 10.1021/jf104395v
关键词
two-dimensional electrophoresis; cross-linking; deamidation; lactosylation; casein; whey; MALDI-TOF MS
资金
- Dairy Australia [UQ11128]
- Australian Research Council
- Dairy Innovation Australia Ltd. [LP0884051]
- Australian Research Council [LP0884051] Funding Source: Australian Research Council
Molecular changes in milk proteins during storage of UHT-treated milk have been investigated using two-dimensional electrophoresis (2-DE) coupled to MALDI-TOF mass spectrometry. UHT-treated samples were stored at three cliFferent temperatures, 4 degrees C, 28 degrees C, and 40 degrees C, for two months. Three main changes could be observed on 2-DE gels following storage. They were (1) the appearance of diffuse staining regions above the position of the monomeric caseins caused by nondisulfide cross-linking of alpha and beta-caseins; (2) the appearance of additional acidic forms of proteins, predominantly of alpha(s1)-casein, caused by deamidation; and (3) the appearance of stacked spots caused by lactosylation of whey proteins. The extent of the changes increased with increased storage temperature. Mass spectrometric analysis of in-gel tryptic digests showed that the crosslinked proteins were dominated by alpha(S1)-casein, but a heterogeneous population of cross-linked forms with alpha(S2)-casein and beta-casein was also observed. Tandem MS analysis was used to confirm deamidation of N(129) in alpha(S1)-casein. MS analysis of the stacked spots reyealed lactosylation of 9/15 lysines in beta-lactoglobulin and 8/12 lysines in alpha-lactalbumin. More extensive analysis will be required to confirm the nature of the cross-links and additional deamidation sites in alpha(S1)-casein as the highly phosphorylated nature of the caseins makes them challenging prospects for MS analysis.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据