کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
606787 1454542 2015 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Surface chemistry and spectroscopy of the β-galactosidase Langmuir monolayer
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی شیمی کلوئیدی و سطحی
پیش نمایش صفحه اول مقاله
Surface chemistry and spectroscopy of the β-galactosidase Langmuir monolayer
چکیده انگلیسی

The changes of interfacial properties of β-galactosidase introduced into different pH environments are investigated through surface chemistry and in situ spectroscopy. Conditions for an optimal Langmuir monolayer formation were firstly obtained by varying the subphase salt concentration and the surface-pressure area isotherm was used to extrapolate the limiting molecular area of the enzyme monolayer to be around 42,000 Å2 molecule−1. Surface pressure stability measurements held at 20 mN/m for 90 min along with compression–decompression cycles revealed no aggregate formation at the air–water interface. Consistent with the data obtained from the isotherm, in situ UV–Vis and fluorescence spectroscopy shows a steep rise in absorbance and photoluminescence intensity correlating to with a switch from a liquid-expanded to a liquid-condensed phase. A decrease in subphase pH increased the electrostatic repulsion as the enzyme was protonated, leading to an expanded monolayer. Infrared absorption–reflection spectroscopy demonstrates that the enzyme adopts mainly β-sheet conformation at the air–water interface before and during the compression.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Colloid and Interface Science - Volume 453, 1 September 2015, Pages 202–208
نویسندگان
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