Inhibition of Rat Brain Microsomal Na+,K+-ATPase by S-Adenosylmethionine |
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| Authors: | Hiroshi Hattori Julian N Kanfer |
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| Institution: | Department of Biochemistry, Faculty of Medicine, The University of Manitoba, Manitoba, Canada |
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| Abstract: | Abstract: Rat brain microsomes were preincubated with S -adenosylmethionine (SAM), MgCl2, and CaCl2, then re-isolated, and the activity of Na+,K+-ATPase determined. SAM inhibited the Na+,K+-ATPase activity compared with microsomes subjected to similar treatment in the absence of SAM. A biphasic inhibitory effect was observed with a 50% decrease at a SAM concentration range of 0.4 μ M -3.2 μ M and a 70% reduction at a concentration range above 100 μ M . Inclusion of either S- adenosylhomocysteine or 3-deazaadenosine in the preincubations prevented the SAM inhibition of Na+,K+-ATPase activity. The inhibition by SAM appeared to be Mg2+- or Ca2+-dependent. |
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| Keywords: | S-Adenosylmethionine Na+ K+-ATPase Rat brain microsomes |
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