Kaplia A A, Kravtsov A V
O.V.Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv.
Ukr Biokhim Zh (1978). 1997 Jul-Aug;69(4):3-8.
The relative stabilities to SDS inactivation of the rat brain Na(+)-ATPase catalytic subunit isoforms in the conditions of the surface charge modulation and temperature modification of the physical state of the membrane lipids were examined. The higher sensitivity of the Na+,K(+)-ATPase a1-isoform than a+ to SDS inactivation occurs under the conditions of the detergent treatment of microsomes at pH 7.5 and room temperature. The decrease in pH in ATP-free medium up to 6.2 or temperature elevation up to 37 degrees C eliminates the differences in SDS sensitivity of the Na+,K(+)-ATPase isoforms. The enhancement of the SDS binding with a subunit due to changes in membrane surface charge in the first case or increase of accessibility of the protein intramembrane regions for detergent due to the decrease of the packing density of the boundary lipids in the second case are supposed.
在膜脂物理状态的表面电荷调节和温度改变的条件下，研究了大鼠脑Na(+)-ATP酶催化亚基同工型对SDS失活的相对稳定性。在pH 7.5和室温下对微粒体进行去污剂处理的条件下，Na+,K(+)-ATP酶a1同工型比a+对SDS失活具有更高的敏感性。在无ATP培养基中pH降低至6.2或温度升高至37℃可消除Na+,K(+)-ATP酶同工型对SDS敏感性的差异。推测在第一种情况下，由于膜表面电荷的变化增强了SDS与亚基的结合；在第二种情况下，由于边界脂质堆积密度的降低增加了去污剂对蛋白质膜内区域的可及性。
