Synergistic Inhibition of Fructose 1,6-Bisphosphatase by Fructose 2,6-Bisphosphate and Adenosine Monophosphate in Round Spermatids of Rats |
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| Authors: | MASAHISA NAKAMURA AKIRA SUZUKI SHOICHI OKINAGA KIYOSHI ARAI |
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| Affiliation: | Department of Obstetrics and Gynecology, School of Medicine, Teikyo University, 2-11-1 Kaga, Itabashi-ku, Tokyo 173, Japan;Department of Biology, School of Education, Waseda University, 1-6-1 Nishi-Waseda, Shinjuku-ku, Tokyo 160, Japan |
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| Abstract: | The effects of adenosine monophosphate (AMP) and fructose 2, 6-bisphosphate (fruc-2, 6-P2) on the key-enzyme of gluconeogenesis, fructose 1, 6-bisphosphatase (fruc-P2ase; D-fructose 1, 6-bisphosphate 1-phosphohydrolase, EC 3.1.3.11) in spermatid extract from rat testes were studied. The fruc-P2ase activity in the spermatids of rats was suppressed by AMP and fruc-2, 6-P2. The inhibition of fruc-2, 6-P2 was much stronger at low than at high substrate concentrations, and enhanced synergistically with AMP. The substrate saturation curve was changed by fruc-2, 6-P2 hyperbolic to sigmoidal. Furthermore, the concentration of AMP that decreased the activity to 50% was much lower in the presence than in the absence of fruc-2, 6-P2. These results indicate the possibility that gluconeogenesis in spermatids of rats is controlled by AMP and fruc-2, 6-P2. |
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