Analysis of the activity and identification of enzymes after separation of cytosol proteins in mouse liver by microscale nondenaturing two-dimensional electrophoresis

Separation of Lysozyme-Ovotransferrin Complexes and the Cooperative Role of Their Components in Egg White

A complex of ovotransferrin and lysozyme was directly isolated from egg white using an anti-transferrin antibody-immobilized membrane after antiserum proteins were separated by non-denaturing two-dimensional electrophoresis and transferred onto a membrane. The complex retained lysozyme activity that catalyzes the breakdown of peptidoglycans in the bacterial cell wall at the β1-4 bond between N-acetylmuramic acid and N-acetylglucosamine residues. The activity of the purified lysozyme was suppressed to 6.4% in the presence of 1 μmol Fe2+, whereas that of the mixture of the purified lysozyme and ovotransferrin was maintained at 58%. The activity of the purified lysozyme was suppressed to 35% in the presence of 10 nmol Fe3+, whereas that of the mixture of the purified lysozyme and ovotransferrin was maintained at 66%. Furthermore, the bacteriolytic activity against Bacillus subtilis of egg white with reduced glycoproteins such as ovotransferrin was assessed, and the bacteriolytic activity was found to be suppressed in the presence of Fe2+ and Fe3+. This suppression was ions, thereby alleviating the inhibition of lysozyme activity by iron ions. A complex of ovotransferrin and lysozyme is efficient because ovotransferrin effectively captures iron ions near lysozyme. Thus, protein complexes containing enzymes can be applied to control their activity.

Electrophoretic injection and reaction of dye-bound enzymes to protein and bacteria within gel

Three-dimensional (3D) cell cultures within gels are used to examine physiological reactions between cells, including bacteria and macromolecules such as enzymes. Using non-denaturing electrophoresis, an anionic Coomassie Brilliant Blue (CBB) dye successfully bound to enzymes such as trypsin and lysozyme, and reacted with a protein and a bacterium within a gel. Both CBB-bound trypsin and lysozyme retained their enzymatic activities and migrated toward the anode in non-denaturing electrophoresis. CBB-bound trypsin successfully digested the iron-binding protein, transferrin, within the gel. Furthermore, the activity of esterase extracted from the bacteria, Bacillus subtilis was analyzed by the non-denaturing electrophoresis containing both the bacteria and the CBB-bound lysozyme after the bacteriolysis of the bacteria by the addition of CBB-bound lysozyme. This method can be applied to deliver enzymes to organisms including bacteria within 3D cell cultures.

Antibacterial activity of lysozyme-binding proteins from chicken egg white

The purpose of this study was to establish a method for determining the bacteriolytic activity after separation of lysozyme-binding proteins from egg white. Lysozyme-binding proteins such as ovotransferrin and ovalbumin were separated by non-denaturing two-dimensional electrophoresis (2DE) and transferred to a membrane. The lysozyme activity of the separated and immobilized egg white proteins was assessed directly to produce a non-denaturing 3D map of the egg white proteins by incorporating an axis that combined each spot's lysozyme-activity with the non-denaturing 2DE pattern. Lysozyme-ovotransferrin and lysozyme-ovalbumin complexes could be reconstructed in vitro after the cathode end fraction containing lysozyme was added to purified ovotransferrin and ovalbumin, respectively. These complexes retained lysozyme activity even after separation by non-denaturing 2DE. Furthermore, when the lysozyme-ovotransferrin complex from egg white was extracted after separation by isoelectric focusing by replacing the cathodic sodium hydroxide solution with phosphoric acid solution, the complex possessed bacteriolytic activity against both Bacillus subtilis and Escherichia coli. These methods can be applied to investigate protein complexes possessing bacteriolytic activity against a wide range of both Gram-positive and Gram-negative bacteria.

Hydrolytic Activity of Esterase-Antibody Complexes Retained Within Gel Capsules After Complex Isolation

Delipidation in biological samples is important for some diagnostic tests and protein analyses. Lipids in the samples can be hydrolyzed by native esterases (ESs) within gel capsules after ES, and ES-antibody complexes are specifically trapped, extracted, and separated. Acrylamide and agarose gel capsules containing complexes of ES antibody were produced after the complexes were extracted using protein A-immobilized membranes, separated by non-denaturing electrophoresis, and stained by colloidal silver using glucose as a reductant. ES activity of ES-antibody complexes within the gel capsule was significantly higher than that in the complexes with the control antibodies upon isolation, separation, and detection of the complex. In addition, lipids bound to human serum albumin decreased after human plasma was treated with gel capsules containing ES-antibody complexes. We demonstrate that the gel capsule containing ES-antibody complexes can be successfully isolated using techniques described in this study. Furthermore, delipidation of human plasma is obtained by incubation with the gel capsule. These results indicate that surplus materials such as lipids in biological samples can be removed or reduced by gel capsule containing enzymes.

Retaining activity of enzymes after capture and extraction within a single-drop of biological fluid using immunoaffinity membranes

The purpose of this study was the measurement of enzyme activity within a single-drop of biological fluid after micropurification. Esterase and lactate dehydrogenase (LDH) retained their enzymatic activities after being captured by membrane-immobilized antibodies, which were prepared by non-denaturing two-dimensional electrophoresis, transferred to polyvinylidene difluoride and then stained by Ponceau S. The activities of both enzymes were also measured after being captured by antibodies and biotinylated antibodies bound to membrane-immobilized protein A or avidin, respectively. After esterase and LDH were captured from biological samples by membrane-immobilized protein A or avidin, their activities were semi-quantitatively measured on the surface of the membrane using fluorescence determination. More than 51% of enzyme activities were retained even after the enzymes were captured by biotinylated antibody bound to membrane-immobilized avidin and eluted by rinsing with 5μL of 1% Triton X-100, compared with the activities of the enzyme on the immunoaffinity membrane.

Proteomic analysis of cellular soluble proteins from human bronchial smooth muscle cells by combining nondenaturing micro 2DE and quantitative LC-MS/MS. 1. Preparation of more than 4000 native protein maps

Soluble proteins of human bronchial smooth muscle cells (HBSMC) were separated by nondenaturing micro 2DE and a 30 mm × 40 mm area of the CBB-stained slab gel (1.0 mm thick) was cut into 1.1 mm × 1.1 mm squares, then the proteins in the 972 gel pieces (squares) were applied to quantitative LC-MS/MS. Grid-cutting of the gel was employed to; (i) ensure the total analysis of the proteins in the area, (ii) standardize the conditions of analysis by LC-MS/MS, (iii) reconstruct the protein distribution patterns from the quantity data [1]. Totally 4323 proteins were identified in successfully analyzed 967 squares and the quantity distribution of each was reconstructed as a color density pattern (a native protein map). The quantity of the proteins distributed from 3.6% to 1 × 10(-5) % of the total protein quantity in the grid area. Each protein map was characterized by several features, including the position of quantity peak square, number of detected squares, and degree of concentration (focused or dispersed). About 4% of the proteins were detected in 100 or more squares, suggesting that they might be ubiquitous and interacting with other proteins. In contrast, many proteins showed more concentrated quantity distribution and the quantity peak positions of 565 proteins with a defined degree of concentration were summarized into a quantity peak map. These results for the first time visualized the distribution patterns of cellular proteins on a nondenaturing 2D gel.

A microfluidic device containing membrane-immobilized antibodies for successively capturing cytosolic enzymes

A microfluidic device containing membrane-immobilized anti-esterase (ES) antibodies and anti-lactate dehydrogenase (LDH) antibodies was prepared. The membrane was prepared by transferring antibodies that had been separated by non-denaturing two-dimensional electrophoresis to a polyvinylidene difluoride membrane, which was then stained and cut into small pieces (16 mm(2)). In this microfluidic device, >0.014 Unit mL(-1) of the purified porcine carboxylesterase was specifically captured by membrane-immobilized anti- ES antibodies and >147 Unit mL(-1) of purified porcine LDH was specifically captured by membrane-immobilized anti-LDH antibodies. Furthermore, ES and LDH in micro-scale aliquots of porcine liver cytosol were successively captured by membrane-immobilized antibodies in the device, and the enzyme activities were quantitatively analyzed by spectrofluorometry. The results indicate that the microfluidic device containing membrane-immobilized antibodies can be used to investigate the activities of several types of intact enzymes.

Micro-scale extraction and analysis of intact carboxylesterase after trapping on an immunoaffinity membrane surface

Porcine liver carboxylesterase was captured using an immunoaffinity membrane, which was prepared by separating an anti-porcine esterase antibody using non-denaturing two-dimensional electrophoresis, followed by transfer to a polyvinylidene difluoride membrane and staining. The activity of this esterase was 0.008 units after it was captured in the tiny spaces (4 mm(2)) of this membrane and eluted by rinsing with 5 μL of aspartic acid solution. The molecular mass of the eluted esterase was m/z 61,885 according to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry after the purification of this enzyme from the porcine liver cytosol. The purified enzyme's activity was inhibited by 6,9-diamino-2-ethoxyacridine, and this inhibition was retained even after extracting the enzyme from the immunoaffinity membrane. These results indicate that micro-scale extraction and analysis of a carboxylesterase are possible when the enzyme is trapped using an immunoaffinity membrane and eluted with aspartic acid.

Selection of artificial valve for the patients on hemodialysis

The selection of artificial valve for the hemodialysis patients is still controversial. Initially ACC/AHA guideline recommended using mechanical valve because of concern on the durability of bioprosthesis after replacement on the dialysis patients; however, revised guideline deleted that recommendation. Although many reports recognized rapid deterioration of bioprosthesis mainly due to calcification after valve replacement, there is no difference on survival between both types of valve. The recently conducted meta-analysis reported the same conclusions. Actually the long-term survival of the dialysis patients is poorer than that of non-dialysis people; however, it differs according to the etiology of renal failure. For example, the long-term survival of the non-diabetic patients seems longer than that of diabetic patients requiring longer durability of artificial valve. According to ACC/AHA guideline and the meta-analysis, surgeon should not hesitate to use bioprosthetic valve; however, surgeon should consider stratification of the dialysis patients by prediction for the long survival of each patient.

Analysis of activity of esterase captured onto an immunoaffinity membrane

BACKGROUND

Specific proteins in biological fluids can be captured on an immunoaffinity membrane after polyclonal anti-porcine liver esterase antibodies are separated by non-denaturing 2-dimensional electrophoresis (2-DE) and transferred onto the membrane. The enzymatic activities of these captured proteins can then be monitored by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).

METHODS

Polyclonal anti-porcine liver esterase antibody was separated by non-denaturing 2-DE, transferred onto a polyvinylidene difluoride membrane and stained with Ponceau S. Esterase activity was examined by enzyme activity staining and MALDI-TOF MS after antigens, including purified carboxylesterase from porcine liver and cytosolic esterase from porcine retina, were captured on the immunoaffinity membrane.

RESULTS

Esterase activity was detected on the immunoaffinity membrane after the enzyme was captured. Phosphatidylcholine hydrolysis by the esterase was monitored after the esterase was captured onto the membrane and attached to the target plate for MALDI-TOF MS.

CONCLUSIONS

This method could be used to analyze changes in enzymatic activity under biological conditions such as health and disease conditions using immunoaffinity membranes and MALDI-TOF MS.

Direct trapping and analysis of hemoglobin in flowing fluid using membrane-immobilized anti-haptoglobin antibody

Haptoglobin is known to bind to hemoglobin during intravascular hemolysis. Membrane-immobilized anti-haptoglobin antibody, which was produced after antibody was isolated by non-denaturing two-dimensional electrophoresis, was transferred to a polyvinylidene difluoride membrane and was stained using Ponceau S. The proteins bound to the membrane-immobilized anti-haptoglobin antibody were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and matrix-assisted laser desorption ionization/time-of-flight mass spectrometry. Hemoglobin was specifically obtained when the membrane-immobilized anti-haptoglobin antibody was incubated with human serum obtained from hemolysis blood. Furthermore, hemoglobin in the flowing fluid was captured by the membrane-immobilized anti-haptoglobin antibody and analyzed directly. The results indicate that hemolysis can be examined by direct trapping and analysis of hemoglobin under physiological conditions.

Direct analysis of retinal dehydrogenase activity on an electroblotting membrane following separation by non-denaturing two-dimensional electrophoresis

The reaction from retinal to retinoic acid catalyzed by retinal dehydrogenase on a polyvinylidene difluoride (PVDF) membrane was examined using laser desorption ionization time of flight mass spectrometry (LDI-TOF MS) when the enzyme was separated by non-denaturing two-dimensional electrophoresis (2-DE), transferred onto the membrane, and stained without impairing the enzyme activity. Furthermore, the enzyme was analyzed by de novo sequencing using electrospray ionization tandem mass spectrometry (ESI-MS/MS) after proteins from mouse liver were separated by non-denaturing 2-DE, blotted onto the membrane, and stained. The results indicated that the reported methods could be applied for the direct examination of changes in retinoid catalyzed by enzymes on such membranes.

Hydrolytic activity of lipase on anion-exchange solid phase column after separation and electrotransfer by non-denaturing electrophoresis

This study reports the initial separation of phospholipase C-alpha from porcine retina using non-denaturing two-dimensional gel electrophoresis (2-DE). Detection was by negative staining and then its hydrolytic activity was estimated using alpha-naphthyl acetate in a 2-DE gel. A spot of phospholipase C-alpha separated by 2-DE was excised. It was then electrophoretically transferred to an anion-exchange solid phase column after 40 mg, equal to dry weight of the solid resin from the cartridge (Accell Plus QMA, Waters Corporation), was packed into a disposable 1 ml syringe to make an anion-exchange solid phase column. Phosphatidylcholine was hydrolyzed in the anion-exchange solid phase column containing phospholipase C-alpha. The results indicated that a column with hydrolytic activity could be produced once lipases separated by non-denaturing 2-DE were transferred to the solid phase column.

Analysis of lipid hydrolytic activity by esterase on blotting membrane followed by separation using non-denaturing two-dimensional gel electrophoresis

After separation by microscale non-denaturing two-dimensional gel electrophoresis (2DE) and transferring to a blotting membrane, major proteins are detected by a staining of direct blue 71 in a neutral solution. The carboxylesterase on the membrane hydrolyzes phosphatidylcholine after the spot of carboxylesterase is excised from the membrane, and incubated with phosphatidylcholine. Lipids of human serum proteins and the purified human high density lipoprotein (HDL) are removed by enzymatic hydrolysis when human serum proteins and the purified HDL are respectively incubated with the spot of carboxylesterase on the membrane. These results indicate that carboxylesterase on the membrane hydrolyzes not only lipids such as phosphatidylcholine but also lipids of lipoproteins such as HDL after separation by the 2DE, transferring to the membrane and staining without impairing the activity. These results also indicate that a micro-immobilized enzyme reactor on the membrane can be produced when biological enzymes are separated by microscale 2DE, transferred to the membrane and stained without impairing their activities.

Detection of activity and mass spectrometric identification of mouse liver carboxylesterase and aldehyde dehydrogenase separated by non-denaturing two-dimensional electrophoresis after extraction with detergents

To examine the activities and identity of enzymes associated with organelles such as microsomes and mitochondria, proteins from mouse liver were extracted using the non-ionic detergents Nonidet P-40 (NP-40), polyoxyethylene sorbitan monooleate (Tween 80), polyoxyethylene isooctylphenyl ester (Triton X), n-octyl beta-D-glucoside (octyl glycoside) or anionic detergent sodium dodecylsulfate (SDS) after the removal of cytosolic proteins. The proteins extracted by detergents were separated by non-denaturing two-dimensional electrophoresis (2-DE). The activities of esterase and aldehyde dehydrogenase were retained by non-denaturing 2-DE after treatment with each non-ionic detergent, but the activities were reduced or lost when the proteins were extracted with more than 0.5% SDS. For proteomic analysis of the organelle-associated proteins in mouse liver, proteins were separated by non-denaturing 2-DE and were identified using electrospray ionization tandem mass spectrometry (ESI-MS/MS) after the proteins were solubilized by octyl glycoside, NP-40 and 0.1% SDS. Several organelle-associated proteins such as carboxylesterase, aldehyde dehydrogenase, glucose regulated protein and HSP60 were identified. These results indicate that the activities and identity of detergent-soluble enzymes can be examined by this non-denaturing 2-DE and mass spectrometry.

Simultaneous analysis of esterase and transferase activities in cytosol proteins from the bovine retina by using microscale non-denaturing two-dimensional electrophoresis

Esterase and transferase activities were analyzed simultaneously after cytosol proteins in the bovine retina were separated by microscale non-denaturing two-dimensional electrophoresis (2-DE). Esterase activity was specifically inhibited by an esterase inhibitor, 9-amino-1,2,3,4-tetra hydroacridine (tacrine), and transferase activity was specifically inhibited by a glutathione S-transferase (GST) inhibitor, 2-phenyl-1,2-benziso selenazol-3(2H)-one (ebselen). Both esterase and transferase were precipitated when ammonium sulfate was added to the cytosol up to 50% saturation (50% AS fraction), and were detected in the 50% AS fraction by using the 2-DE. After the cytosol proteins in the 50% AS fraction were separated by using non-denaturing 2-DE, polypeptides of the separated proteins were identified by peptide mass fingerprinting and post-source decay analysis by using MALDI-MS, or by immunoreactivity by using a specific antibody. The spots of esterase and transferase activities in the 2-DE pattern were identified as phosphodiesterase and GST, respectively. This simultaneous analysis of enzyme activities can be applied to screen-specific or non-specific medicines which affect enzyme activities.