Castignetti D, Siddiqui A F, Olsen K W
Department of Biology, Loyola University of Chicago, IL 60626.
J Biochem Biophys Methods. 1988 Oct;17(2):119-25. doi: 10.1016/0165-022x(88)90042-5.
A spectrophotometric assay using ferric perchlorate in a perchloric acid solution has been developed to monitor the degradation of the trihydroxamate siderophore deferrioxamine B to monohydroxamates. Using the ferric perchlorate solution and employing various concentrations of acetohydroxamic acid (as the model monohydroxamic acid) while maintaining a constant amount of deferrioxamine B resulted in the shifting of the absorption maximum from that of ferrioxamine B to longer wavelengths and toward that of a pure ferri-acetomonohydroxamic acid solution. A similar result was noted when a cell-free extract, from a bacterium capable of using deferrioxamine B as its sole carbon source, was given the siderophore in a phosphate buffer and aliquots of the enzyme-deferrioxamine B solution were removed for analysis. The assay may thus be used to monitor the formation of the monohydroxamic acid degradation products of the siderophore by the enzyme(s) in the cell-free extract.
已开发出一种分光光度法，该方法在高氯酸溶液中使用高氯酸铁来监测三异羟肟酸铁载体去铁胺B降解为单异羟肟酸的过程。使用高氯酸铁溶液并采用不同浓度的乙酰氧肟酸（作为模型单异羟肟酸），同时保持去铁胺B的量恒定，结果导致吸收最大值从铁胺B的吸收最大值向更长波长移动，并趋向于纯铁 - 乙酰单异羟肟酸溶液的吸收最大值。当将来自能够以去铁胺B作为唯一碳源的细菌的无细胞提取物置于磷酸盐缓冲液中的铁载体中，并取出酶 - 去铁胺B溶液的等分试样进行分析时，也观察到了类似的结果。因此，该测定法可用于监测无细胞提取物中酶使铁载体的单异羟肟酸降解产物的形成。
