We have evaluated the alkylation chemistry first described some years ago by Boyd et al. which is now routinely applied in a commercial instrument. We have found that the low repetitive yields observed during these analyses are due to the formation of a major side product when alkylating the C-terminal thiohydantoin. This side product, resistant to the chemical cleavage methods currently used, was characterized by NMR experiments in solution. We further demonstrate that chemical C-terminal sequence analysis of proteins using the alkylation chemistry is feasable with low picomole amounts of material. High-sensitivity C-terminal sequencing allows a complementary approach by which a protein is first subjected to N-terminal Edman degradation followed by C-terminal sequence analysis, limiting the amount of material necessary for the characterization of the protein under study. This limited C-terminal sequence information is often sufficient to solve problems that cannot be solved by applying any other analytical method commonly used today.
我们评估了几年前Boyd等人首次描述的烷基化
化学,这种
化学现在在商业仪器中常规应用。我们发现,在这些分析中观察到的低重复产率是由于在烷基化C-末端
硫酰
氨基酸时形成了一个主要的副产物。该副产物对当前使用的
化学裂解方法具有抗性,通过NMR实验在溶液中进行了表征。我们进一步证明,使用烷基化
化学进行蛋白质的
化学C末端序列分析是可行的,即使在低皮摩尔量的样品下也能实现。高灵敏度C末端测序提供了一种补充方法,即首先对蛋白质进行N末端Edman降解,然后进行C末端序列分析,从而限制了对研究蛋白质进行表征所需的样品量。这种有限的C末端序列信息通常足以解决目前其他常用分析方法无法解决的问题。