EN
Ca2+-ATPase, the enzyme responsible for maintenance of low resting Ca2+ level in the nerve cell, has been purified from rat cortical, cerebellar and hippocampal synaptosomal membranes by affinity chromatography on Calmodulin-Agarose which followed Reactive Red 120-Agarose column. The enzymes from these three regions ran as broad, monomeric bands on SDS-PAGE with a molecular weight at range 130-138 kDa, and were identified as a Ca2+- ATPase using monoclonal antibody 5F10. Analysis of the kinetic parameters revealed that hippocampal Ca2+-ATPase exhibited 2 times higher affinity for ATP, than cortical and cerebellar enzymes. The affinity for Ca2+ increased in order: cerebellum, cortex, and hippocampus. The differences in kinetic characteristics of purified enzymes, suggest that in adult rat brain the Ca2+-ATPase could be represented at a protein level by the region-dependent combination of several isoforms.