Immobilization of Na, K-ATPase isolated from rat brain synaptic plasma membranes

Rat brain Na,K-ATPase partially purified by SDS from synaptic plasma mem- branes (SPM) was immobilized by adsorption on nitrocellulose (NC), polyvinylidene fluo- ride (PVDF) and glass fiber (GF) membranes. Partial SDS solubilization increased the en- zyme activity by 40 %. With regard to the preservation of the enzyme activity, nitrocellulose was shown to be the optimal support for the immobilization. The enzyme showed the high- est percentage activity (14 %) after 30 min of SPM adsorption, at 20 ºC under the vaccum, with 25 g of proteins per NC disc filter. In addition, adsorption on NC stabilizes the Na,K-ATPase, since the activity was substantial 72 h after adsorption at 20 ºC. After adsorp- tion, the sensitivity of the enzyme to HgCl2 and CdCl2 inhibition was higher. The results show that immobilized Na,K-ATPase SPM can be used as a practical model for the detection of metal ions in different samples.