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Nature of respiratory stimulation in hyperthyroidism: the redox behaviour of cytochrome c
Author(s) -
Schmehl I,
Luvisetto S,
Canton M,
Gennari F,
Azzone G.F
Publication year - 1995
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(95)01211-v
Subject(s) - protonophore , mitochondrion , respiratory chain , electron transport chain , stimulation , cytochrome c oxidase , cytochrome , respiration , chemistry , redox titration , redox , respiratory system , biochemistry , euthyroid , cytochrome c , biophysics , endocrinology , biology , medicine , enzyme , inorganic chemistry , anatomy , hormone
Hyperthyroid mitochondria show an increased K m and V max in the high affinity phase of cytochrome oxidase kinetics. During inhibitor titrations, cytochrome c shows a different redox behaviour in hyperthyroid with respect to protonophore‐treated euthyroid mitochondria. The observations are discussed in terms of a different regulation of electron input and output into the respiratory chain during slip and leak types of uncoupling. In hyperthyroid mitochondria during inhibitor titrations, the pattern of the relationship between uncoupler‐induced extra‐respiration and membrane potential is highly non‐linear. The complex nature of the respiratory stimulation in hyperthyroid mitochondria is discussed.