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Optimized Protocol for the Extraction of Proteins from the Human Mitral Valve
Published on: June 14, 2017
Prosaposin is a novel coenzyme Q10-binding protein
Makoto Hasegawa1, Yorihiro Yamamoto1, Akio Fujisawa1
1School of Bionics, Tokyo University of Technology, 1404-1 Katakura-machi, Hachioji, Tokyo 192-0982, Japan.
Abstract:
Coenzyme Q10 (CoQ10) is essential for mitochondrial ATP production and functions as an important antioxidant in every biomembrane and lipoprotein. Due to its hydrophobicity, a binding and transfer protein for CoQ10 is plausible, and we previously described saposin B as a CoQ10-binding and transfer protein. Here, we report that prosaposin, the precursor of saposin B, also binds CoQ10. As prosaposin is both a secretory protein and integral membrane protein, it is ubiquitous in the body. Prosaposin was isolated from human seminal plasma, and CoQ10 was extracted from hexane solution into the water phase. It was additionally found that immunoprecipitates of mouse brain cytosol generated using two different anti-prosaposin antibodies contained coenzyme Q9. Furthermore, mouse liver cytosol and mouse kidney cytosol also contained prosaposin-coenzyme Q9 complex. These results suggest that prosaposin binds CoQ10 in human cells and body fluids. The significance and role of the Psap-CoQ10 complex in vivo is also discussed.
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