Single-step Enzyme Research Articles

Optimal bioconversion for compound K production from red ginseng root (C.A. Mayer) by sequential enzymatic hydrolysis and its characteristics

Compound K (CK; 20-O-β-(d-glucopyranosyl)-20(S)-protopanaxadiol) is one of the metabolites of ginsenosides contained in red ginseng (RG) and is known to have high bioavailability. This study aimed to establish the optimal conditions for enzyme treatment to convert ginsenosides from RG extract to CK, and to prove the characteristics of bioconverted red ginseng (BRG) extract. CK was not detected in unenzyme-treated RG extract, and in the single-step enzyme treatment, it was produced at less than 4.58 mg/g only in treatment group with Pyr-flo or Sumizyme AC (at 50 °C for 48 h). The highest yield of CK (14.32 mg/g) was obtained by Ultimase MFC treatment at 50 °C for 48 h after treatment with a mixture of Pyr-flo and Rapidase at 50 °C for 24 h. Total polyphenol, 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) (ABTS) radical scavenging activity were higher in BRG than in RG (p < 0.5). High-fat diet (HD) rat fed 1% BRG had significantly lower body weight, heart weight, fat pads (periosteal fat, epididymal fat), serum glucose levels, and hepatic triglyceride levels than those HD rat fed 1% RG (p < 0.05). In conclusion, the sequential enzymatic bioconversion was produces higher CK in RG root extract than single-step enzyme treatment.

Single-step enzyme processing of soybeans into intact oil bodies, protein bodies and hydrolyzed carbohydrates

Abstract To maximize value and minimize waste in soy processing, all major soybean components, i.e., oil, protein and carbohydrate, should be collected and utilized. Existing processing was originally designed to maximize oil extraction. It tends to make protein and carbohydrate separation from remaining meal more difficult and reduce their value. In this study, a single-step sonication-assisted enzyme processing was developed to separate and collect intact oil bodies, protein bodies and hydrolyzed carbohydrates from soybeans. Confocal laser scanning microscopic observations confirmed enzymatic destruction of cell wall and separation of oil bodies and protein bodies by centrifugation. Distributions of oil, protein and carbohydrate were quantitated in the top oil/cream layer, bottom protein-enriched precipitates, and the middle aqueous solution. Effects of the soybean particle size and the concentration of an Aspergillus niger enzyme were investigated. A pulsed ultrasonic treatment at 1.5 W/ml, for 5 min every 3 h during the enzyme processing, was found to significantly improve the performance and separation of oil bodies from protein. 87% of oil bodies were collected from cracked particles of 0.42–1.19 mm in size using, per g particles, 2 ml enzyme that contained 0.62 FPU/ml cellulase, 93 U/ml xylanase, 5.8 U/ml pectinase and 6.4 U/ml α-galactosidase.

Anionic surfactant based reverse micellar extraction of L-asparaginase synthesized by Azotobacter vinelandii.

L-Asparaginase synthesized by Azotobacter vinelandii via submerged fermentation in the presence of sucrose was successfully extracted using Reverse micellar extraction. Single step enzyme purification process was developed by varying the process variables which resulted in maximum specificity and extraction of L-asparaginase. The effect of different variables, including broth pH, addition of alcohol during the forward extraction and pH of the fresh stripping aqueous phase, addition of alcohol and electrolyte during backward extraction process were studied. Lower concentration of butanol resulted in maximum activity of the enzyme during forward extraction while enzyme activity was found to increase further with the addition of higher concentrations of ammonium sulphate during backward extraction. Chromatographic analysis of L-asparaginase peak at ~7.65min was intense for the back extracted sample confirming the maximum purity of L-asparaginase obtained. Purity of L-asparaginase was increased to about 379.68 fold.

Quantitative and Single-step Enzyme Immunosensing Based on an Electrochemical Detection Coupled with Lateral-flow System.

A single-step electrochemical immunochromatography has been developed: the device was based on two pieces of nitrocellulose membrane, a sample pad with anti-mouse IgG antibody labeled with glucose oxidase (GOx-labeled antibody), a conjugate pad with glucose, and a Pt working electrode. Either antibody or antigen was immobilized on the membrane. The addition of a solution containing mouse IgG, a model target, allows for the dissolution of GOx-labeled antibody in the sample pad to form an immunocomplex. The produced immunocomplex was automatically separated by capturing to the antibody immobilized on the membrane with the sandwich structure or by passing through the membrane modified with an antigen for the competitive reaction. The separated GOx label arrived at the conjugate pad with glucose to undergo the enzyme reaction. Hydrogen peroxide generated by this reaction was detected at the Pt electrode prepared on the second nitrocellulose membrane downstream from the conjugate pad. The results demonstrated that the designed immunochromatography can be applied to quantitative detection with a single-step procedure, because both the GOx-labeled antibody for revealing the immunoreactions and the substrate for the enzyme reaction were prepared in the device. Moreover, the initial concentration of the GOx-labeled antibody permitted control of the detectable concentration for mouse IgG.

An efficient protocol for deriving liver stem cells from neonatal mice: validating its differentiation potential.

The success of liver regeneration depends on the availability of suitable cell types and their potential to differentiate into functional hepatocytes. To identify the stem cells which have the ability to differentiate into hepatocytes, we used neonatal liver as source. However, the current protocol for isolating stem cells from liver involves enzymes like collagenase, hyaluronidase exposed for longer duration which limits the success. This results in the keen interest to develop an easy single step enzyme digestion protocol for isolating stem cells from liver for tissue engineering approaches. Thus, the unlimited availability of cell type favors setting up the functional recovery of the damaged liver, ensuring ahead success towards treating liver diseases. We attempted to isolate liver stem derived cells (LDSCs) from mouse neonatal liver using single step minimal exposure to enzyme followed by in vitro culturing. The cells isolated were characterized for stem cell markers and subjected to lineage differentiation. Further, LDSCs were induced to hepatocyte differentiation and validated with hepatocyte markers. Finally, we developed a reproducible, efficient protocol for isolation of LDSCs with functional hepatocytes differentiation potential, which further can be used as in vitro model system for assessing drug toxicity assays in various preclinical trials.

A single-step enzyme immunoassay capillary sensor composed of functional multilayer coatings for the diagnosis of marker proteins.

A single-step, easy-to-use enzyme immunoassay capillary sensor, composed of functional multilayer coatings, was developed in this study. The coatings were composed of substrate-immobilized hydrophobic coating, hydrogel coating, and soluble coating containing an enzyme-labeled antibody. The response mechanism involved a spontaneous immunoreaction triggered by capillary action-mediated introduction of a sample antigen solution and subsequent separation of unreacted enzyme-labeled antibodies and antigen-enzyme-labeled antibody complexes by the molecular sieving effect of the hydrogel. An enzyme reaction at the substrate-immobilized hydrophobic coating/hydrogel coating interface resulted in a protein-selective fluorescence response. An antigen concentration-dependent response was obtained for diagnostic marker protein samples (hemoglobin A1c (HbA1c), 7.14-16.7 mg mL(-1); alpha-fetoprotein (AFP), 1.4-140 ng mL(-1); C-reactive protein (CRP), 0.5-10 μg mL(-1)) that cover a clinically important concentration range. The successful measurement of CRP in diluted serum samples demonstrated the application of this capillary sensor.

Development of a fluorometric microtiter plate-based enzyme assay for arylsulfatase B (MPS VI) using dried blood spots

Mucopolysaccharidosis type VI or Maroteaux–Lamy syndrome is an autosomal recessive lysosomal storage disorder caused by deficiency of arylsulfatase B (ARS-B) enzyme activity. It results in mild to severe multi-organ system failure from accumulation of undigested glycosaminoglycans (GAGs); dermatan sulfate and chondroitin-4-sulfate. We have developed a single-step enzyme assay using a fluorescent substrate and dried blood spots to measure ARS-B activity to identify disease patients. This assay is robust, reproducible, specific and convenient to perform.

ChemInform Abstract: A Review of Cellulosic Biofuel Commercial‐Scale Projects in the United States

AbstractReview: 62 refs.

Combinable poly(dimethyl siloxane) capillary sensor array for single-step and multiple enzyme inhibitor assays

We describe a new method for fabricating a capillary-type sensor, called a combinable poly(dimethyl siloxane) (PDMS) capillary (CPC) sensor. The method for preparing the CPC simplifies enzyme inhibitor assays into a simple, single step assay. The sample inhibitor solution is introduced by capillary action. This triggers the spontaneous dissolution of physically adsorbed fluorescent substrates, and the substrate mixes with the inhibitor. This is followed by competitive reaction with insoluble enzyme to give a fluorescence response. CPC is composed of a convex-shaped PDMS stick containing reagents immobilized in an insoluble coating, and a concave-shaped PDMS stick containing reagents immobilized in a soluble coating. Since the concave-shaped PDMS has a deeper channel than the convex structure, combining these PDMS sticks is like closing the zipper of a "freezer bag". This allows easy fabrication of "thin and long" capillary structures containing different reagents inside the same capillary, without the need for precise alignment. This method allows the immobilization of two reactive reagents, such as enzyme and substrate required for a single step assay, which are typically very difficult to immobilize using commercially available conventional capillaries. Furthermore, by simply arraying various CPCs, the CPC sensor allows multiple assays. Here, we carried out a single-step enzyme inhibitor assay using the CPC. In addition, two independent CPCs were arrayed to demonstrate multiple assaying of a protease inhibitor.

A bioluminescence method for direct measurement of phosphodiesterase activity

We have adapted bioluminescence methods to be able to measure phosphodiesterase (PDE) activity in a one-step technique. The method employs a four-enzyme system (PDE, adenylate kinase (AK) using excess CTP instead of ATP as substrate, pyruvate kinase (PK), and firefly luciferase) to generate ATP, with measurement of the concomitant luciferase-light emission. Since AK, PK, and luciferase reactions are coupled to recur in a cyclic manner, AMP recycling maintains a constant rate of ATP formation, proportional to the steady-state AMP concentration. The cycle can be initiated by the PDE reaction that yields AMP. As long as the PDE reaction is rate limiting, the system is effectively at steady state and the bioluminescence kinetics progresses at a constant rate proportional to the PDE activity. In the absence of cAMP and PDE, low concentrations of AMP trigger the AMP cycling, which allows standardizing the system. The sensitivity of the method enables detection of <1μU (pmol/min) of PDE activity in cell extracts containing 0.25–10μg protein. Assays utilizing pure enzyme showed that 0.2mM IBMX completely inhibited PDE activity. This single-step enzyme- and substrate-coupled cyclic-reaction system yields a simplified, sensitive, reproducible, and accurate method for quantifying PDE activities in small biological samples.

Linear and non-linear pressure dependence of enzyme catalytic parameters

The pressure dependence of enzyme catalytic parameters allows volume changes associated with substrate binding and activation volumes for the chemical steps to be determined. Because catalytic constants are composite parameters, elementary volume change contributions can be calculated from the pressure differentiation of kinetic constants. Linear and non-linear pressure-dependence of single-step enzyme reactions and steady-state catalytic parameters can be observed. Non-linearity can be interpreted either in terms of interdependence between the pressure and other environmental parameters (i.e., temperature, solvent composition, pH), pressure-induced enzyme unfolding, compressibility changes and pressure-induced rate limiting changes. These different situations are illustrated with several examples.

Linear closed mini DNA generated by the prokaryotic cleaving-joining enzyme TelN is functional in mammalian cells.

For application of DNA in gene medicine plasmid or viral DNA is usually used as a vector for the gene of interest. To generate DNA with a minimum of foreign DNA sequences, we used the prokaryotic telomerase, protelomerase TelN, of bacteriophage N15. This is a novel enzyme with cleaving-joining activity, which is required for the formation of linear prophage DNA with closed ends in lysogenic bacteria. Acting on a telomere resolution site telRL, the protelomerase converts circular plasmid DNA into linear covalently closed dumbbell-shaped molecules ("doggybones") in a single-step enzyme reaction. Two such sites were inserted into an expression plasmid flanking a gene of interest. This is cleaved and joined by means of the protelomerase, yielding linear closed mini DNA coding for green fluorescent protein (EGFP) or interleukin-12 (IL-12). Upon transient transfection of human embryonal kidney cells, EGFP was expressed at higher levels from linear closed molecules than from linear open molecules generated by restriction endonucleases for comparison. The level of transcription was comparable to that observed for the parental plasmid DNA. To test whether the linear closed mini DNA molecules are functional in vivo the B16F10/C57BL/6 melanoma metastasis model was applied, where injection of IL-12-expressing DNA inhibits metastasis formation in the lung. The anti-metastatic effect of the IL-12-expressing linear closed DNA was equal or higher than that of the parental plasmid DNA. Therefore, the TelN/ telRL system is well suited to generate linear closed mini DNA with high stability and a minimum of foreign nucleotide sequences.

A radioisotopic assay of picomolar concentrations of coenzyme A in liver tissue

A single-step enzyme assay using [ 14C]palmitic acid and bacterial acyl-coenzyme A synthetase (EC 6.2.1.3) is described for the determination of reduced coenzyme A (CoASH) levels in liver samples. Use of this technique provides a rapid and accurate determination of CoASH in the range 1–250 pmol. Application of the method to the quantitation of CoASH in samples of human liver tissue and rat liver homogenate, isolated hepatocytes, and mitochondria is described.