Surface Effect of Nano-Roughened Yttria-Doped Zirconia on Salivary Protein Adhesion

Iqbal, Muhammad N.; Shen, Zhijian; Bengtsson, Tore; Eriksson, Mirva

doi:10.3390/ma14216412

Cited by 1 publication

(14 citation statements)

References 22 publications

(24 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The DNP-enhanced 13 C NMR spectra in Figure 4b 52 The DNP-enhanced 15 N NMR spectra shown in Figure 4c reveal typical backbone amide signals with 15 N chemical shifts between −260 and −280 ppm as well distinct resonances of Nε and Nη atoms of arginine at around −305 and −315 ppm, respectively, and that from the NH 3 + group of lysine at −355 ppm. 52 The DNPenhanced 13 C and 15 N NMR spectra of the free and biosorbed α-amylase are essentially identical; hence, no conformational changes of the enzyme structures are expected to have occurred on the adsorption of the α-amylase on the MSPs. The similarities of the 13 C and 15 N NMR spectra for adsorbed α-amylase and free α-amylase were used to conclude that adsorbed α-amylase was folded.…”

Section: Dynamic Nuclear Polarization Mas Nmr Characterizationmentioning

confidence: 99%

“…DNP MAS NMR experiments were performed at a magnetic field of 9.4 T with a Bruker Avance Neo spectrometer, a 263 GHz gyrotron, and a 3.2 mm low-temperature probe head at a MAS rate of 12 kHz. The sample temperature was approximately 105 K. The magnetic field was set so that the microwave irradiation occurred at the same position as the positive-enhancement maximum for the AMUPol polarizing agent, which was used to enable the DNP enhancement of the signal-to-noise in the 13 C and 15 N NMR spectra. The DNP-enhanced cross-polarization (CP) 13 C and 15 N MAS experiments employed a SPINAL-64 heteronuclear decoupling scheme, whereas the DNP-enhanced 1 H− 13 C CP-HETCOR correlation experiment employed homonuclear 1 H decoupling of the frequency-switched Lee− Goldburg (FSLG) type.…”

Section: Dnp−nmr Characterizationmentioning

confidence: 99%

“…From preliminary MAS NMR experiments performed on α-amylase adsorbed in SBA-15, it was concluded that the signal-to-noise ratio in the spectra was not high enough to determine if the α-amylase was folded in the adsorbed state without the use of DNP experiments. For the detailed analysis, 1 H NMR spectra were recorded under the conditions of fast MAS, and DNP-enhanced 13 C and 15 N NMR spectra were recorded at low-temperature and under MAS. The DNP was applied to increase the 13 C and 15 N NMR sensitivity at natural isotope abundance.…”

Section: Dynamic Nuclear Polarization Mas Nmr Characterizationmentioning

confidence: 99%

“…For the detailed analysis, 1 H NMR spectra were recorded under the conditions of fast MAS, and DNP-enhanced 13 C and 15 N NMR spectra were recorded at low-temperature and under MAS. The DNP was applied to increase the 13 C and 15 N NMR sensitivity at natural isotope abundance. 49 We used AMUPol as a polarizing agent, which is recognized as appropriate for use in biological systems according to recent literature.…”

Section: Dynamic Nuclear Polarization Mas Nmr Characterizationmentioning

confidence: 99%

“…10 The apparent reduced activity of enzymes has been attributed to the sizespecific adsorption of the enzymes (amylase and lipase) from complex gastric fluids and studied in vitro, ex vivo, and in vivo. 14,15 The digestive enzyme α-amylase belongs to the glycoside hydrolase family and cleaves glucan links in polysaccharides, such as starch and glycogen. It is responsible for the release of maltose, etc.…”

Section: ■ Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Activity and Stability of Nanoconfined Alpha-Amylase in Mesoporous Silica

et al. 2023

Self Cite

View full text Add to dashboard Cite

Mesoporous silica particles (MSPs) have been studied for their potential therapeutic uses in controlling obesity and diabetes. Previous studies have shown that the level of digestion of starch by α-amylase is considerably reduced in the presence of MSPs, and it has been shown to be caused by the adsorption of α-amylase by MSPs. In this study, we tested a hypothesis of enzymatic deactivation and measured the activity of α-amylase together with MSPs (SBA-15) using comparably small CNP-G3 (2-chloro-4-nitrophenyl alpha-d-maltotrioside) as a substrate. We showed that pore-incorporated α-amylase was active and displayed higher activity and stability compared to amylase in solution (the control). We attribute this to physical effects: the coadsorption of CNP-G3 on the MSPs and the relatively snug fit of the amylase in the pores. Biosorption in this article refers to the process of removal or adsorption of α-amylase from its solution phase into the same solution dispersed in, or adsorbed on, the MSPs. Large quantities of α-amylase were biosorbed (about 21% w/w) on the MSPs, and high values of the maximum reaction rate (V max) and the Michaelis–Menten constant (K M) were observed for the enzyme kinetics. These findings show that the reduced enzymatic activity for α-amylase on MSP observed here and in earlier studies was related to the large probe (starch) being too large to adsorb in the pores, and potato starch has indeed a hydrodynamic diameter much larger than the pore sizes of MSPs. Further insights into the interactions and environments of the α-amylase inside the MSPs were provided by 1H fast magic-angle spinning (MAS) nuclear magnetic resonance (NMR) and 13C/15N dynamic nuclear polarization MAS NMR experiments. It could be concluded that the overall fold and solvation of the α-amylase inside the MSPs were nearly identical to those in solution.

show abstract