[The role of conformational changes in the functioning of brain Na,K-ATPase].
In the experiments with enzyme preparations of Na,K-ATPase from normal brain tissue (NBT) and tumorous brain tissue (TBT) the following data were established: 1) the cooperativity of Na,K-ATPase with Na+ from NBT is temperature-dependent, the Hill coefficient (nH) at 37, 27.0-30.5 and 20-22 degrees C being 1.80 +/- 0.07, 1.30 +/- 0.09 and 1.10 +/- 0.08, respectively; the cooperativity of Na+ with Na,K-ATPase from TBT was absent; 2) the cooperativity for ouabain (nH-1.30 +/- 0.05) was revealed only in the case of Na-pump from TBT; 3) the protective effect of ATP against the inhibitory action of pCMB is temperature-dependent and differs significantly in enzyme preparations from NBT and TBT; 4) the parameters of the temperature inactivation of enzyme preparations at 45-52 degrees C, especially the change of entropy (delta S*) were different in the case of NBT and TBT; 5) a peptide fraction isolated from sheep brain differently inhibited the Na,K-ATPase from NBT and TBT. In conclusion, these data demonstrate that there are significant differences in functioning of Na,K-ATPase from NBT and TBT, and that besides lipid-protein interactions the local domenic conformational changes in the enzyme molecule may play a definite role in these differences.
Tsil'mer
M K
MK
Tiakhepyld
L Ia
LIa
Salum
T T
TT
Sillard
R G
RG
Kask
R R
RR
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000201:enzymology*; D001932:Brain Neoplasms / Q000201:enzymology; D002234:Carbodiimides / Q000494:pharmacology; D002729:Chloromercuribenzoates / Q000494:pharmacology; D006801:Humans; D010042:Ouabain / Q000494:pharmacology; D011487:Protein Conformation / Q000187:drug effects; D051381:Rats; D012016:Reference Values; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013696:Temperature
D002234:Carbodiimides; D002729:Chloromercuribenzoates; D010042:Ouabain; D000255:Adenosine Triphosphate; D000254:Sodium-Potassium-Exchanging ATPase
O roli konformatsionnykh izmeneniĭ v funktsionirovanii Na,K-ATFazy mozga.