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. Author manuscript; available in PMC: 2010 Feb 13.
Published in final edited form as: Methods Enzymol. 2008;441:339. doi: 10.1016/S0076-6879(08)01219-6

Table 19.1.

Chemical structures, properties, and theoretical m/z values of nitrohydroxytryptophan and its derivatives by MALDI analysis

Structures Comments Theoretical
m/z of the
protonated
ions
graphic file with name nihms-172284-t0003.jpg The protonated molecular ion is abundantly formed if the synthetic nitrohydroxytryptophan is used. In contrast, the peak intensity will be much lower if using an HPLC eluate from a protein digest. 266.23
graphic file with name nihms-172284-t0004.jpg Photodecomposition product of nitrohydroxytryptophan following laser exposure: there is a loss of one oxygen atom from the nitro group. The fragmented ion will be predominant if the initial concentration of nitrohydroxytryptophan is low. 250.23
graphic file with name nihms-172284-t0005.jpg Photodecompostion product of nitrohydroxytryptophan following laser exposure: note the loss of two oxygen atoms from the nitro group. This fragmented ion is not observed consistently. 234.23
graphic file with name nihms-172284-t0006.jpg The compound obtained after treatment with dithionite. 236.25