Institute of Biomedicine, Sahlgrenska Academy at University of Gothenburg, Göteborg, Sweden.
Proteomics. 2010 Apr;10(8):1694-8. doi: 10.1002/pmic.200900782.
Thyroglobulin is an iodinated glycoprotein (m.w. 660 kD) required for the storage and formation of thyroid hormone. Thyroglobulin was digested by trypsin in distilled water and the resulting peptides were identified by TOF-secondary ion mass spectrometry, using TFA as a matrix to catalyze the ionization of the peptides. Cryostate sections of pig thyroid glands were incubated with trypsin in distilled water, followed by deposition of TFA. The sections were analyzed with TOF-secondary ion mass spectrometry, and the peptides formed were identified through comparison with the peptides of the thyroglobulin reference sample. The thyroglobulin fragments were localized in the thyroid follicle cells with a spatial resolution of 3 microns, a mass resolution m/Delta m of >6000 and a mass accuracy of <60 ppm. The thyroglobulin was found localized heterogeneously in the follicle cells. The heterogeneity may be due to thyroglobulin synthesis, uptake and degradation or globules representing insoluble polymers of thyroglobulin considered to be a mechanism for storing hormone at high concentrations.
甲状腺球蛋白是一种碘化糖蛋白（分子量 660kD），是甲状腺激素储存和形成所必需的。甲状腺球蛋白在蒸馏水中被胰蛋白酶消化，所得肽段通过 TOF-二次离子质谱进行鉴定，使用 TFA 作为基质来催化肽段的电离。猪甲状腺的冷冻切片在蒸馏水中与胰蛋白酶孵育，然后沉积 TFA。使用 TOF-二次离子质谱对切片进行分析，并通过与甲状腺球蛋白参考样品的肽段进行比较来鉴定形成的肽段。甲状腺球蛋白片段在甲状腺滤泡细胞中定位，空间分辨率为 3 微米，质量分辨率 m/Delta m 大于 6000，质量精度小于 60ppm。发现甲状腺球蛋白在滤泡细胞中不均匀定位。这种异质性可能是由于甲状腺球蛋白的合成、摄取和降解，或者是代表甲状腺球蛋白不溶性聚合物的小球体，被认为是在高浓度下储存激素的一种机制。
