CAJ | 학술논문

利用两相法化纯化质膜微囊,研究了分布西北沙地区的两种生态型芦苇(Phragmites communis trih.)水生芦苇和重度盐化草甸芦苇,分别简称为水芒和盐芦)叶片质膜H+- ATPase的部分性质.结果显示,与水芦相比,盐芦质膜H+-ATPase的ATP水解活性升高,Km值由1.27mmol\l降至Vmax没有显著差异.并且该酶活性对温度的敏感必玫PH谱型也发生了变化.以对硝基苯磷酸盐为底物,低浓度时盐芦的的质膜H+-ATPase水解活性有差异.钡酸盐抑制实验表明,两种生态的质膜H+-ATPase磷酸-酶区的催化性质不同.胰酶对质膜H+-ATPase活性的活化谱型也存在差异,说明该酶C末端的结构或性质发生了变化.此外,与水芦相比,盐芦质膜H+-ATPase的质子泵活性的耦联程度也升高了.以上结果明,当芦苇从水生环境向盐渍环境过渡时,质膜H+-ATPase的催化性质发生了变化,这些变化可能是由酶结构的修饰和不同的同工酬酶谱引起的.H+-ATPase催化性质的变化可能是对盐渍生境的适应性反应.
이용량상법화순화질막미낭,연구료분포서북사지구적량충생태형호위(Phragmites communis trih.)수생호위화중도염화초전호위,분별간칭위수망화염호)협편질막H+- ATPase적부분성질.결과현시,여수호상비,염호질막H+-ATPase적ATP수해활성승고,Km치유1.27mmol\l강지Vmax몰유현저차이.병차해매활성대온도적민감필매PH보형야발생료변화.이대초기분린산염위저물,저농도시염호적적질막H+-ATPase수해활성유차이.패산염억제실험표명,량충생태적질막H+-ATPase린산-매구적최화성질불동.이매대질막H+-ATPase활성적활화보형야존재차이,설명해매C말단적결구혹성질발생료변화.차외,여수호상비,염호질막H+-ATPase적질자빙활성적우련정도야승고료.이상결과명,당호위종수생배경향염지배경과도시,질막H+-ATPase적최화성질발생료변화,저사변화가능시유매결구적수식화불동적동공수매보인기적.H+-ATPase최화성질적변화가능시대염지생경적괄응성반응.
Plasma membrane (PM) vesicles of the leaves of two ecotypes of reed (Phragmites communis Trin.), swamp reed (SR) and heavy salt meadow reed (HSMR) growing in the desert region of Northwest China, were purified by two-phase partitioning and the properties of their PM H+-ATPases (EC 3.6.1.35)were compared. The specific activity of this enzyme was greater in HSMR than in SR and the Km lower (1.27 mmol/L in SR and 0.30 mmol/L in HSMR), and the Vmax of ATP hydrolysis activity showed no significant difference between the two ecotypes. The PM H+-ATPase was more sensitive to denaturing temperatures in HSMR than in SR, and the pH profile also showed a slight difference, suggesting that the catalytic mechanism of this enzyme was different in HSMR compared with that in SR. The p -nitrophenyl phosphate (PNPP) hydrolysis activity of H+-ATPase was higher in HSMR than in SR at low concentrations of PNPP, but showed no difference at high PNPP concentration. The Km for PNPP hydrolysis was 3.61 mmol/L and 1.92 mmol/L in SR and HSMR, respectively. And the Vmax of PNPP hydrolysis showed no significant difference in the two reed ecotypes. An experiment with the inhibitor vanadate showed that the catalytic mechanisms of the phosphatase domain of the ATPase were different in the two ecotypes. The data obtained following trypsin treatment showed a difference in the enzyme activity pattern, suggesting that there existed a possible change in the C-terminus of the ATPase, either in the structure or in the property or both of them. In addition, compared with SR, the ATP-dependent H+ pumping activity of ATPase and the coupling between proton transport and ATP hydrolysis in HSMR were increased. These results indicated that the properties of PM H+-ATPase were changed in HSMR with compared to those in SR,which might include enzyme modifications and different isoforms expressed. The alterations of the properties of this enzyme might be an adaptive response to the habitat.