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AMP promotes oxygen consumption and ATP synthesis in heart mitochondria through the adenylate kinase reaction: an NMR spectroscopy and polarography study
Author(s) -
Doliba Nicolai M.,
Babsky Andriy M.,
Doliba Nataliya M.,
Wehrli Suzanne L.,
Osbakken Mary D.
Publication year - 2015
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.3089
Subject(s) - adenylate kinase , atp synthase , chemistry , biochemistry , mitochondrion , adenine nucleotide , nuclear magnetic resonance spectroscopy , nucleotide , biophysics , biology , enzyme , stereochemistry , gene
Adenylate kinase plays an important role in cellular energy homeostasis by catalysing the interconversion of adenine nucleotides. The goal of present study was to evaluate the contribution of the adenylate kinase reaction to oxidative ATP synthesis by direct measurements of ATP using 31 P NMR spectroscopy. Results show that AMP can stimulate ATP synthesis in the presence or absence of ADP. In particular, addition of 1 mM AMP to the 0.6 mM ADP superfusion system of isolated superfused mitochondria (contained and maintained in agarose beads) led to a 25% increase in ATP synthesis as measured by the increase in β ATP signal. More importantly, we show that AMP can support ATP synthesis in the absence of ADP, demonstrated as follows. Superfusion of mitochondria without ADP led to the disappearance of ATP γ , α and β signals and the increase of P i . Addition of AMP to the medium restored the production of ATP, as demonstrated by the reappearance of γ , α and β ATP signals, in conjunction with a decrease in P i , which is being used for ATP synthesis. Polarographic studies showed Mg 2+ dependence of this process, confirming the specificity of the adenylate kinase reaction. Furthermore, data obtained from this study demonstrate, for the first time, that different aspects of the adenylate kinase reaction can be evaluated with 31 P NMR spectroscopy. Copyright © 2015 John Wiley & Sons, Ltd. SIGNIFICANCE OF RESEARCH PARAGRAPH The data generated in the present study indicate that 31 P NMR spectroscopy can effectively be used to study the adenylate kinase reaction under a variety of conditions. This is important because understanding of adenylate kinase function and/or malfunction is essential to understanding its role in health and disease. The data obtained with 31 P NMR were confirmed by polarographic studies, which further strengthens the robustness of the NMR findings. In summary, 31 P NMR spectroscopy provides a sensitive tool to study adenylate kinase activity in different physiological and pathophysiological conditions, including but not exclusive of, cancer, ischemic injury, hemolytic anemia and neurological problems such as sensorineural deafness.