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Interaction of diiodothyronines with isolated cytochrome c oxidase
Author(s) -
Fernando Goglia,
Antonia Lanni,
Jörg Barth,
Bernhard Kadenbach
Publication year - 1994
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(94)00476-5
Subject(s) - cytochrome c oxidase , chemistry , stimulation , allosteric regulation , triiodothyronine , mitochondrion , respiration , cytochrome , electron transport complex iv , oxidase test , enzyme , hormone , cytochrome c , biochemistry , stereochemistry , endocrinology , biology , anatomy
Diiodothyronines (3,3′‐T 2 and 3,5‐T 2 ) stimulate the activity of isolated cytochrome c oxidase (COX) from bovine heart mitochondria. Maximal stimulation of activity (about 50%) is obtained with 3,3′‐T 2 at pH 6.4 and with 3,5‐T 2 at pH 7.4. In contrast, 3,5,3′‐triiodothyronine (T 3 ) exhibited no or little stimulation of COX activity. Binding of the hormones to COX leads to conformational changes as shown by modified visible spectra of the oxidized enzyme. It is suggested that ‘short‐term’ effects of thyroid hormones on mitochondrial respiration are at least partly due to the allosteric interaction of diiodothyronines with the COX complex.