کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5030807 1470932 2018 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Lipidic liquid crystalline cubic phases for preparation of ATP-hydrolysing enzyme electrodes
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Lipidic liquid crystalline cubic phases for preparation of ATP-hydrolysing enzyme electrodes
چکیده انگلیسی


- Lipidic liquid crystalline cubic phase is promising as hosting material for membrane proteins.
- Monoolein derived cubic phase retains activity of membrane protein, Na+/K+-ATPase.
- Bioelectrode based on ATPase in cubic phase is useful for ATPase activity measurements.

The lipidic liquid-crystalline cubic phase (LCP) is a membrane-mimetic material useful for the stabilization and structural analysis of membrane proteins. Here, we focused on the incorporation of the membrane ATP-hydrolysing sodium/potassium transporter Na+/K+-ATPase (NKA) into a monoolein-derived LCP. Small-angle X-ray scattering was employed for the determination of the LCP structure, which was of Pn3m symmetry for all the formulations studied. The fully characterized NKA-LCP material was immobilized onto a glassy carbon electrode, forming a highly stable enzyme electrode and a novel sensing platform. A typical NKA voltammetric signature was monitored via the anodic reaction of tyrosine and tryptophan residues. The in situ enzyme activity evaluation was based on the ability of NKA to transform ATP to ADP and free phosphate, the latter reacting with ammonium molybdate to form the ammonium phosphomolybdate complex under acidic conditions. The square-wave voltammetric detection of phosphomolybdate was performed and complemented with spectrophotometric measurement at 710 nm. The anodic voltammetric response, corresponding to the catalytic ATP-hydrolysing function of NKA incorporated into the LCP, was monitored at around + 0.2 V vs. Ag/AgCl in the presence or absence of ouabain, a specific NKA inhibitor. NKA incorporated into the LCP retained its ATP-hydrolysing activity for 7 days, while the solubilized protein became practically inactive. The novelty of this work is the first incorporation of NKA into a lipidic cubic phase with consequent enzyme functionality and stability evaluation using voltammetric detection. The application of LCPs could also be important in the further development of new membrane protein electrochemical sensors and enzyme electrodes.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biosensors and Bioelectronics - Volume 100, 15 February 2018, Pages 437-444
نویسندگان
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