Biochemical and thermodynamic characterization of de novo synthesized β-amylase from fenugreek

α-Amylase purified and characterized from fenugreek (Trigonella foenum-graecum) showed substantial anti-biofilm activity against Staphylococcus aureus MTCC740

Starch hydrolyzing α-amylase from germinated fenugreek (Trigonella foenum-graecum) has been purified 104-fold to apparent electrophoretic homogeneity with a final specific activity of 297.5 units/mg. SDS-PAGE of the final preparation revealed a single protein band of 47.5 kDa, supported by LC/MS analysis and size-exclusion chromatography on the Superdex 200 (ÄKTA-FPLC). α-Amylase exhibited maximum activity at pH 5.5. An activation energy (Ea) of 9.12 kcal/mol was found to exist in the temperature range of 20 to 90 °C. When substrate concentrations were evaluated between 0.5 and 10 mg/mL, the Km and Vmax values for starch were observed to be 1.12 mg/mL and 384.14 μmol/min/mg, respectively. The major substrate starch exhibited high specificity for fenugreek α-amylase. In the presence of EDTA (5 mM), the activity was lost, however, it could be largely reversed with the addition of calcium. Furthermore, an effort was made to assess the ability of fenugreek seed-derived partially purified (DEAE-cellulose enzyme) and purified α-amylase to disperse inside 48 h-old biofilms of Staphylococcus aureus MTCC740. The outcomes clearly demonstrated that the purified and partially purified α-amylase both exhibited strong biofilm dispersion activity.

Efficacy and safety of permeation enhancers: a kinetic evaluation approach and molecular mechanism study in the skin

This study sought to provide approach for evaluating and predicting the efficacy and safety of permeation enhancers on the basis of their kinetic distribution behavior in the skin dictated by physicochemical properties. Herein, the efficacy-safety regularity of eight permeation enhancers were studied with ex vivo skin permeation study, small-angle X-ray scattering, MTT assay, H&E staining, and in vivo skin erythema analysis, classifying into the following three categories: high enhancement-low irritation, medium enhancement-high irritation, and low enhancement-low irritation. These three modes were positively correlated with the distribution amount of permeation enhancers in the skin layers and verified by the in vitro tape-stripping study. The kinetic parameter, effective-safety index (I_ES), was proposed to describe the regularity of enhancement effect tendency and irritation risk, and the relationship between I_ES and physicochemical properties of permeation enhancers was analyzed with multiple regression analysis. According to the results of modulated temperature differential scanning calorimetry and dielectric spectrum, permeation enhancers with high lipophilicity and low polarity had I_ES > 1, suggesting high enhancement effect and low irritation due to their higher affinity with the stratum corneum (SC) than with epidermis (EP). Permeation enhancers with medium lipophilicity and medium polarity exhibited 0 <I_ES ≤ 1, showing medium enhancement effect and high irritation, as determined by their comparable affinity with the SC and epidermis (EP). However, permeation enhancers with low lipophilicity and high polarity had I_ES → 0, demonstrating low enhancement effect and irritation, as indicated by their poor affinity with the SC. In summary, different physicochemical properties of permeation enhancers influenced their affinities with skin layers, resulting in their different enhancement effect and irritation potential. This study will provide a theoretical basis and criteria for evaluating and predicting the safety and efficacy of permeation enhancers, which will enable a more rational selection of permeation enhancers in the optimization of transdermal patches.

Denaturant Induced Equilibrium Unfolding and Conformational Transitional Studies of Germinated Fenugreek β-Amylase Revealed Molten Globule like State at Low pH

BACKGROUND

β-Amylase (EC 3.2.1.2) is a maltogenic enzyme, which releases β-maltose from the non-reducing end of the substrates. The enzyme plays important roles for the production of vaccine, maltiol and maltose rich syrups. Apart from these applications the enzyme protects cells from abiotic as well as oxidative damage. The enzyme is βwell characterized in βplants and microbes and crystal structures of β-amylases βhave been βobtained from sweet potato, soybean and Bacillus cereus.

OBJECTIVE

Find out correlation between structural and functional stability induced by change in pH, temperature and chaotropes.

METHODS

Activity, intrinsic fluorescence, extrinsic fluorescence, near- and far- ultraviolet circular dichroism spectroscopic measurements were performed.

RESULTS

Peaks about 208 nm and 222 nm obtained by near-ultraviolet circular dichroism correspond to α-helix whereas peak at 215 nm shows presence of β-sheet. At pH 2.0, absence of tertiary structures, exposed of hydrophobic regions and presence of substantial secondary structures, revealed the existence of molten globule like state. Temperature induced denaturation studies showed that the enzyme was stable up to 75 ºC and the process was found to be irreversible in nature. Chaotropes dependent equilibrium unfolding studies revealed that at low concentration of chaotropes, ellipticity and intrinsic fluorescence βintensity were βdecreased βwhereas βenzymatic activity remained unchanged, which revealed fenugreek β-amylase is multi-domains enzyme and catalytic βdomain βis more βstable compare to non-catalytic domain. Moreover, the transition was sigmoidal and non-coincidental.

CONCLUSION

Results indicate the probable existence of intermediate states that might perform significant role in physiological process and biotechnological applications.

Immobilization of fenugreek β-amylase onto functionalized tungsten disulfide nanoparticles using response surface methodology: Its characterization and interaction with maltose and sucrose

In this communication, fenugreek β-amylase was immobilized onto functionalized tungsten disulfide nanoparticles through cross-linker glutaraldehyde and successful immobilization was confirmed by SEM, AFM and FTIR spectroscopy. To make the process economical and efficient, optimization of independent variables was carried out using Box-Behnken design of response surface methodology. Approximately similar predicted (85.6%) and experimental (84.2%) immobilization efficiency revealed that the model is suitable for design of space. Optimum temperature was calculated to be 60 °C. After immobilization, an increased K_m (2.12 times) and a decreased V_max (0.58 times), indicated inaccessibility of active site residues to the substrate. The immobilized enzyme retained 77% relative activity after 10 uses whereas 40% residual activity was obtained after 120 days. An increased half-life with concomitantly decreased kinetic rate constant revealed that the immobilized enzyme is more stable at a higher temperature and the process followed first-order kinetics (R² > 0.93). The limit of detection for maltose and sucrose fluorescence biosensor was found to be 0.052 and 0.096 mM, respectively. Thermodynamic parameters such as changes in Gibbs free energy (ΔG < 0), enthalpy (ΔH > 0) and entropy (ΔS >0) revealed that the process is spontaneous and endothermic, driven by hydrophobic interactions. Thermo-stability data at higher temperature for the immobilized enzyme makes it a suitable candidate for industrial applications in the production of maltose in food and pharmaceutical industries. Furthermore, fluorescence biosensor could be used to detect and quantify maltose and sucrose to maintain the quality of industrial products.