Tandem mass spectrometry for the multiplex and quantitative analysis of enzyme activities in dried blood spots on newborn screening cards has emerged as a powerful technique for early assessment of lysosomal storage diseases. Here we report the design and process-scale synthesis of substrates for the enzymes α-l-iduronidase, iduronate-2-sulfatase, and N-acetylgalactosamine-4-sulfatase that are used for newborn screening of mucopolysaccharidosis types I, II, and VI. The products contain a bisamide unit that is hypothesized to readily protonate in the gas phase, which improves detection sensitivity by tandem mass spectrometry. The products contain a benzoyl group, which provides a useful site for inexpensive deuteration, thus facilitating the preparation of internal standards for the accurate quantification of enzymatic products. Finally, the reagents are designed with ease of synthesis in mind, thus permitting scale-up preparation to support worldwide newborn screening of lysosomal storage diseases. The new reagents provide the most sensitive assay for the three lysosomal enzymes reported to date as shown by their performance in reactions using dried blood spots as the enzyme source. Also, the ratio of assay signal to that measured in the absence of blood (background) is superior to all previously reported mucopolysaccharidosis types I, II, and VI assays.
                                    用于对新生儿筛查卡上干血斑中的酶活性进行多重定量分析的串联质谱法已成为早期评估溶酶体贮积病的强大技术。在这里,我们报告了用于新生儿粘
多糖贮积症 I、II 和 VI 型筛查的 α-
L-艾杜糖醛酸酶、艾杜糖醛酸-2-
硫酸酯酶和 N-乙酰半
乳糖胺-4-
硫酸酯酶底物的设计和工艺规模合成。 。该产品含有双酰胺单元,据推测该单元在气相中容易质子化,从而提高了串联质谱法的检测灵敏度。该产品含有苯甲酰基,为廉价的
氘化提供了有用的位点,从而有助于制备用于准确定量酶产物的内标。最后,这些试剂的设计考虑到易于合成,从而可以扩大制备规模,以支持全球新生儿溶酶体贮积病筛查。新试剂为迄今为止报道的三种溶酶体酶提供了最灵敏的测定,如它们在使用干血斑作为酶源的反应中的性能所示。此外,检测信号与无血液(背景)下测量的信号之比优于所有先前报道的粘
多糖贮积症 I、II 和 VI 型检测。