posted on 2020-03-12, 16:36authored byMaricruz Mamani-Huanca, Ana Gradillas, Alberto Gil de la Fuente, Ángeles López-Gonzálvez, Coral Barbas
The alteration of
modified amino acid (MAA) profiles in biological
samples is related to important cellular, physiological, and pathological
processes. To achieve the interpretation of their biochemical relevance,
it is critical to define their whole chemical spectrum using metabolomic
research works. We present a detailed in-source fragmentation (ISF)
study based on the mechanisms of the major fragmentation reactions
observed of diagnostic ions (DIs) generated in positive electrospray
ionization for 57 amino acid standard compounds using capillary electrophoresis
coupled with high-resolution mass spectrometry. The DIs presented
and our in-house fragment library allowed us to establish a workflow
for targeted extraction of MAAs. We present key examples showing successful
findings such as the identification of N2-methyl-l-lysine, which provides insight into the lysine
methylome. The experimental results presented prove that the use of
ISF data, when combined with a thorough study of the fragmentation
mechanisms, constitutes an informative source of accurate molecular
identity.