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Regulation of ATP hydrolase activity of the F 0 ‐F 1 complex of rat‐liver mitochondria during early hepatic regeneration
Author(s) -
Buckle Malcolm
Publication year - 1986
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(86)81110-3
Subject(s) - atpase , atp hydrolysis , liver regeneration , in vivo , biology , mitochondrion , submitochondrial particle , hydrolase , adenosine , biochemistry , enzyme , guinea pig , regeneration (biology) , chemistry , medicine , endocrinology , microbiology and biotechnology
Submitochondrial particles prepared from rat liver in the early phase of hepatic regeneration possess a reduced F 1 content with respect to F 0 in intact F 0 F 1 ‐H + ‐ATPase complexes. Analysis of ATP hydrolysis showed a significant difference in both ESMP and isolated F 1 with regard to the higher affinity K m values ( K m,1 ) obtained from Eadie‐Hofstee plots. Both ESMP and F 1 from regenerating rat liver showed much lower apparent K m,1 values (0.04 and 0.03 mM, respectively) than the corresponding controls (0.08 mM for both ESMP and F 1 ). Data presented here show that the residual F 1 moieties have an altered kinetic pattern with regard to the competitive inhibitor adenosine 5'‐[β,γ‐imido]triphospate ( K 1 ESMP from regenerating rat liver = 0.67 μM, K 1 ESMP from control rat liver = 2.03 μM). This difference in affinity for [β,γ‐imido]‐ATP is also seen in isolated F 1 (K 1 regenerating rat liver = 0.04 μM, K 1 control rat liver = 0.22 μM). These data indicate that during the disruptive retrodifferential phase of hepatic regeneration, changes at the level of surviving F 1 sectors of the F 0 ‐F 1 ATPase may play a physiological role in preventing ATP hydrolysis in vivo in the brief period of low ΔμH + , induced by the presence of non‐F 1 ‐associated F 0 proton‐conducting pathways.