6 research outputs found
Calcium Binding and Transport by Coenzyme Q
Coenzyme Q10 (CoQ10) is one of the essential
components of the mitochondrial electron-transport chain
(ETC) with the primary function to transfer electrons along
and protons across the inner mitochondrial membrane (IMM).
The concomitant proton gradient across the IMM is essential
for the process of oxidative phosphorylation and consequently
ATP production. Cytochrome P450 (CYP450) monoxygenase
enzymes are known to induce structural changes in a variety of
compounds and are expressed in the IMM. However, it is
unknown if CYP450 interacts with CoQ10 and how such an
interaction would affect mitochondrial function. Using voltammetry, UV�vis spectrometry, electron paramagnetic resonance
(EPR), nuclear magnetic resonance (NMR), fluorescence microscopy and high performance liquid chromatography�mass
spectrometry (HPLC�MS), we show that both CoQ10 and its analogue CoQ1, when exposed to CYP450 or alkaline media,
undergo structural changes through a complex reaction pathway and form quinone structures with distinct properties. Hereby, one
or both methoxy groups at positions 2 and 3 on the quinone ring are replaced by hydroxyl groups in a time-dependent manner. In
comparison with the native forms, the electrochemically reduced forms of the new hydroxylated CoQs have higher antioxidative
potential and are also now able to bind and transport Ca2þ across artificial biomimetic membranes. Our results open new
perspectives on the physiological importance of CoQ10 and its analogues, not only as electron and proton transporters, but also as
potential regulators of mitochondrial Ca2þ and redox homeostasis
Risk for chronic kidney disease in the general population: Italian reports for World Kidney Days 2007-2009
The prevalence of chronic kidney disease (CKD) has rapidlyincreased in recent decades in many countries, leading toconsistent economic implications. Considering the fact thatpatients surviving to CKD often develop end-stage renal disease,the number of patients requiring replacement therapyreached 169/million population (pmp) in Italy in 2004 and342 pmp in the Unites States. Furthermore, CKD weighs onpatients survival with a considerably increased cardiovascular(CV) morbidity and mortality