The correct molecular weight of myoglobin, a common calibrant for mass spectrometry.
The correct molecular weight of myoglobin, a common calibrant for mass spectrometry.
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肌红蛋白的正确分子量，肌红蛋白是质谱分析的常用校准物。
DOI：
10.1002/rcm.1290060108
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Biemann,K
中科院分区：
文献类型：
--
作者：
Zaia,J;Annan,RS;Biemann,K
来自马热肌、马骨骼肌和抹香鲸的肌红蛋白被广泛用作各种质谱方法的校准标准品或测试化合物。在文献中报告的所有此类情况下，使用的分子量值（分别为16950.5和17199）是基于这样的假设，即153个氨基酸长的蛋白质中的氨基酸122是天冬酰胺，忽略了已发表的建议，即它是天冬氨酸。由于基质辅助激光解吸质谱法的质量分配准确度为±0.01%，电喷雾离子化为± 0.0025%，因此误差为1/17000。包含来自市售马心脏和马骨骼肌红蛋白的氨基酸122的胰蛋白酶肽、后者的脱辅基肌红蛋白以及抹香鲸肌红蛋白的胰蛋白酶和胰凝乳蛋白酶肽的离子的质荷比证明，在这两种蛋白质中，氨基酸122确实是天冬氨酸，而不是天冬酰胺。马肌红蛋白胰蛋白酶肽和抹香鲸肌红蛋白糜蛋白酶肽的[M+H]+离子的碰撞诱导解离谱进一步证实了这一发现。因此，马肌红蛋白的正确分子量为16951.49，抹香鲸蛋白的正确分子量为17199.91。
Myoglobins from horse heat muscle, horse skeletal muscle and sperm whale are widely used as calibration standards or test compounds for various mas spectrometric methodologies. In all such cases reproted in the literature, a molecular weight value is used (16950.5 and 17199, respectively) which is based on the assumption that amino acid 122 in this 153 amino‐acid‐long protein is asparagine, overlooking a published suggestion that it is aspartic acid instead. Since the mass assignment accuracy for matrix‐assisted laser desorption mass spectrometry is reproted to be ±0.01% and for electrospray ionization ±0.0025%, and error of one mass unit in ∼ 17000 would be significant. The mass‐to‐charge ration of ions of the tryptic peptide encompassing amino acid 122 derived from commercially available horse heart and horse skeletal myoglobins, the apomyoglobin of the latter, and the tryptic and chymotryptic peptide of sperm whale myoglobin proved that in both proteins amino acid 122 is indeed aspartic acid, rather than asparagine. This finding was further confirmed by the collision‐induced dissociation sectra of the [M+H]+ ions of the tryptic peptides from the horse myoglobins and the chymotriptic peptide from sperm whale myoglobin. Thus, the correct molecular weight of horse myoglobinis 16951.49 and that of the sperm whale protein is 17199.91.