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Creatine kinase function in mitochondria isolated from gravid and non‐gravid guinea‐pig uteri
Author(s) -
Clark Joseph F.,
Kuznetsov Andrey V.,
Khuchua Zaza,
Veksler Vladimir,
Ventura-Clapier Renée,
Saks Valdur
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)00525-7
Subject(s) - creatine kinase , creatine , mitochondrion , oxidative phosphorylation , medicine , endocrinology , respiration , biology , uterus , guinea pig , chemistry , biochemistry , anatomy
Mitochondria from gravid and non‐gravid guinea pig uteri were isolated and respiratory rates examined to determine the responses to ATP, ADP and creatine. It was found that mitochondria isolated from gravid uterus had (i) a markedly higher respiration rate in state 3; (ii) a greater activation of respiration by creatine in the presence of 0.1 mM ATP and (iii) an elevated specific activity of mitochondrial creatine kinase. It was shown by a competitive enzyme method, using pyruvate kinase to trap ADP, that despite the presence of creatine kinase in the mitochondria, there is no functional coupling between mitochondrial creatine kinase and oxidative phosphorylation as has been shown for striated muscle. It is suggested that the function of uterine Mi‐CK is to favour high energy phosphate turnover in conditions of increased metabolic demand in gestating uterine smooth muscle.