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Ca 2+ regulation of thyroid NADPH‐dependent H 2 O 2 generation
Author(s) -
Dupuy C.,
Dème D.,
Kaniewski J.,
Pommier J.,
Virion A.
Publication year - 1988
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 - 10.1016/0014-5793(88)81358-9
Subject(s) - egta , chemistry , calcium , fraction (chemistry) , chaps , enzyme , incubation , particulates , thyroid , chromatography , biochemistry , endocrinology , biology , organic chemistry
A thyroid particulate fraction contains an NADPH‐dependent H 2 O 2 ‐generating enzyme which requires Ca 2+ for activity. A Chaps solubilized extract of the thyroid particulate fraction partially purified by DEAE chromatography did not show a dependence on Ca 2+ for activity. Preincubation of the particulate fraction with Ca 2+ yielded a preparation insensitive to Ca 2+ . The non‐particulate fraction obtained after incubation of the particles in the presence of Ca 2+ was able to inhibit, in the presence of EGTA, the Ca 2+ ‐desensitized particulate fraction and the enzyme isolated on DEAE. It is concluded that the reversible Ca 2+ activation of the NADPH‐dependent H 2 O 2 generation was modulated in porcine thyroid tissue by (a) calcium‐releasable inhibitor protein(s).