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Novel immunoassays to detect methionine adenosyltransferase activity and quantify S ‐adenosylmethionine
Author(s) -
Hao Xiujuan,
Zhou Min,
Li Huijun,
Angres Isaac A.
Publication year - 2017
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1002/1873-3468.12631
Subject(s) - methionine adenosyltransferase , chemistry , methylation , methionine , stimulation , immunoassay , biochemistry , adenosine triphosphate , cytoplasm , microbiology and biotechnology , biology , endocrinology , dna , antibody , amino acid , immunology
We present a novel real‐time immunoassay to measure methionine adenosyltransferase (MAT) activity that integrates the MAT‐catalyzed reaction of Met and adenosine triphosphate to produce S ‐adenosylmethionine (SAM) and a highly sensitive immunoassay to specifically quantify SAM simultaneously. The cellular localization of SAM and S ‐adenosylhomocysteine varies with cell proliferation status: in normal cells, they are found mostly in the cytoplasm, but localize to the nucleus in proliferating cells. MAT‐I/ III activity is stimulated by Met, but inhibited by S ‐nitrosoglutathione, and the methylation index (MI) increases after Met stimulation of L02 cells. Met and S ‐nitrosoglutathione inhibit MAT‐ II activity, and the MI decreases after Met stimulation of HepG2 cells. The method described provides a significant advancement in the field for the measurement of MAT activity under various conditions.