High-performance ion-exchange chromatography of plasma proteins

Probing Blood Plasma Protein Glycosylation with Infrared Spectroscopy

The health state of an individual is closely linked to the glycosylation patterns of his or her blood plasma proteins. However, obtaining this information requires cost- and time-efficient analytical methods. We put forward infrared spectroscopy, which allows label-free analysis of protein glycosylation but so far has only been applied to analysis of individual proteins. Although spectral information does not directly provide the molecular structure of the glycans, it is sensitive to changes therein and covers all types of glycosidic linkages. Combining single-step ion exchange chromatography with infrared spectroscopy, we developed a workflow that enables the separation and analysis of major protein classes in blood plasma. Our results demonstrate that infrared spectroscopy can identify different patterns and global levels of glycosylation of intact plasma proteins. To showcase the strengths and limitations of the proposed approach, we compare the glycoforms of human and bovine alpha-1-acid glycoproteins, which exhibit highly variable global levels of glycosylation. To independently evaluate our conclusions, the glycan moieties of human alpha-1-acid glycoprotein were further analyzed using an established glycomics workflow. Importantly, the chromatographic separation of blood plasma improves the detection of aberrant glycoforms of a given protein as compared to infrared spectroscopy of bulk plasma. The presented approach allows a time-efficient comparison of glycosylation patterns of multiple plasma proteins, opening new avenues for biomedical probing.

Harnessing the Potential of Blood Proteins as Functional Ingredients: A Review of the State of the Art in Blood Processing

Blood is generated in very large volumes as a by-product in slaughterhouses all around the world. On the one hand, blood generation presents a serious environmental issue because of its high pollutant capacity; however, on the other hand, blood has the potential to be collected and processed to generate high-added-value food ingredients based on its exceptional nutritive value and its excellent functional properties. In this paper, we review the current state of the art for blood processing, from collection to final recovery of protein isolates, the functional properties of blood, impact of processing on functional properties, and potential applications as food ingredients. Furthermore, future challenges are outlined for this underutilized and abundant product from the meat industry.

Albumin as a marker of plasma transudation in experimental skin lesions

Liquid chromatography measurements of albumin levels were obtained for experimental incision wounds, excoriations, and heat and freezing injuries of different ages. Hemoglobin levels in tissue specimens were measured and an equivalent amount of blood-related albumin was subtracted from the analysis results. In specimens taken immediately after death, the mean albumin level as compared to control skin was increased by about 2-fold in freezing injuries aged 60 min. In all other lesions, the same increase was observed even after 30 min. The mean albumin level was about 3-fold as compared with the control skin in excoriations aged 30 min, heat and freezing injuries aged 4 h, and incision wounds aged 12 h. An approximately 5-fold increase was seen in heat and freezing injuries aged 1 and 2 weeks. A marked decrease occurred in mean albumin levels in all lesions aged 4 weeks. An increase in albumin in wounds and excoriations was demonstrable also in specimens taken 3 days postmortem. Postmortem hypostasis resulted in a 1.1 to 1.4-fold increase in mean albumin levels in wounds and excoriations inflicted 1 min postmortem.

Macroporous poly(glycidyl methacrylate-triallyl isocyanurate-divinylbenzene) matrix as an anion-exchange resin for protein adsorption

A novel macroporous poly(glycidyl methacrylate-triallyl isocyanurate-divinylbenzene) matrix was prepared by a radical suspension copolymerization. The matrix contained epoxy groups, so diethylaminohydroxypropyl groups were coupled to the matrix, leading to an anion-exchange resin. We studied the components, surface and pore structures of the anion-exchange resin by Fourier transform infared spectroscopy and scanning electron microscopy (SEM). SEM observations showed that the resin abounded in macropores as large as 3 to 8 microns both in the surface and the interior. The back-pressure of the column packed with the resin was modest even at a high flow-rate (60.2 cm/min). Then, bovine serum albumin (BSA) was used as a model protein to examine the adsorption properties of the anion-exchange resin. The results showed that under optimum conditions the resin had a capacity as high as 22.8 mg BSA/g wet resin, or 68.7 mg/g dry resin. The adsorbed protein could be desorbed by increasing the liquid phase ionic strength. Most importantly, the matrix had little nonspecific adsorption for BSA before introducing the ion-exchange groups.

Selective precipitation of human hemoglobin by organic solvents and metal cations

The interaction of human hemoglobin with several organic solvents and metal cation has been studied in order to obtain selective precipitation of hemoglobin from solution. Alcohols, and preferably the mixture ethanol: butanol added to a final concentration of 8% (v/v) 1-butanol was found to be superior in this respect, giving close to selective precipitation of hemoglobin from whole blood lysates. An equally specific precipitation was achieved by using zinc-chloride in 10-15 molar excess to hemoglobin. Contrary to organic solvents, complex formation with Zn2+ resulted in a reversible precipitation enabling renaturation using strong chelating agents. Specificity of the hemoglobin-precipitating agents was verified by chromatographic and electrophoretic studies. Applications of the presented methods in analytical chemistry and in the isolation and purification of blood proteins are discussed.

Study of the chromium binding in plasma of patients on continuous ambulatory peritoneal dialysis

The distribution of chromium (Cr) among the proteins in plasma of three continuous ambulatory peritoneal dialysis (CAPD) patients and in dialysis solutions was studied with 'in vitro' and 'in vivo' 51Cr-labelled plasma. Radiolabelling allows the kinetics of newly added Cr to be investigated. The separation of the proteins was achieved by ion exchange fast protein liquid chromatography, ensuring quantitative recoveries of the 51Cr activity, transferrin and albumin. In all fractions the proteins were qualitatively characterised by iso electric focusing. The concentrations of transferrin and albumin were determined by nephelometry. The 51Cr distribution among the plasma proteins was similar for the three patients. The 51Cr activity was mainly bound to transferrin and, in the beginning of the incubation, in a lesser degree also to albumin. After 1-6 h a shift was observed of the 51Cr from albumin to an unidentified low molar mass complex (+/- 5000 Da). Two 51Cr species showed up in the subsequently drained dialysate, but they could not be identified.

Immunologic studies of a horse with lymphosarcoma

Immunological, clinical, and pathological investigations were conducted on a horse with lymphosarcoma. The immunological status was investigated by measuring the level of antibodies by single radial immunodiffusion test and the ability of lymphocytes to proliferate in response to mitogens. Multiple immunological abnormalities were noted in this horse. They were; (1) decreased IgM, IgG, and IgA levels in the serum despite hyperproteinemia; (2) increased in-vitro spontaneous lymphoproliferation which reflects augmented mitosis; (3) decreased lymphoproliferative response to T cell stimulants (e.g. Concanavalin-A (Con-A)) suggesting impaired T cell activation; (4) presence of immunosuppressive factors in serum as demonstrated by in-vitro lymphocyte culture systems. Clinical pathology findings revealed an unusual monoclonal alpha peak in the serum and morphologically abnormal lymphocytes distributed throughout the body. Serum fractionated by fast protein liquid chromatography (FPLC) revealed that the immunosuppressive factors were found in this abnormal alpha peak. The immunopathological findings in this horse are discussed.

Detection of allogeneic Qa/TL and Ly specificities on murine tumor cells with IgD in tumor-regressor serum

Serum from C3H/He mice, which show regression of MM2 tumor cells after transplantation and removal (regressor serum, RS) contains non-gammaglobulin components that cross-react with various tumor cells of mice [22, 23]. In addition to tumor cells, various allogeneic lymphocytes are also susceptible to an RS-dependent lymphocyte-mediated cytotoxic reaction. To identify tumor cell surface antigens that cause the cross-reactive host response, the serum components were analyzed by absorption of RS with allogeneic lymphocytes. RS components were found to recognize allogeneic lymphocyte antigens including Qa-2 and Ly6.2. Specificity for the Qa-2 antigen was further tested using Qa-2-congenic mice. The expression of Qa-2 antigen was detected on the surfaces of MM2 and other tumor cells derived from H-2k mice (seven among nine cell lines tested) by a membrane immunofluorescence method using a Qa-2-specific mAb. Physical characteristics of the Qa-2-specific component in RS were determined and found to differ from those of regular IgGs but to be similar to those of IgDs. Using an enzyme-linked immunosorbent assay with an IgD-specific mAb and Qa-2-lacZ fusion protein, the existence of IgD in RS with specificity for Qa-2 was confirmed. These results suggest that the RS component with Qa-2 specificity is an IgD, the specificity and physiological role of which are unknown.

Carbohydrates as a tool for oriented immobilization of antigens and antibodies

A biospecific sorbent for the isolation of ovalbumin antibodies was prepared by coupling of ovalbumin via its periodate-oxidized carbohydrate moiety to bead cellulose modified with adipic acid dihydrazide. The anti-ovalbumin IgG fraction isolated on this sorbent from immune rabbit serum contained only antibodies against protein determinants of ovalbumin. Thus, when these IgG were immobilized through their carbohydrate moieties to cellulose beads it became possible to prepare a biospecific sorbent for concanavalin A by oriented adsorption of ovalbumin. Ovalbumin was specifically adsorbed via its protein moiety and its carbohydrate part remained free for interaction with concanavalin A.

Protein purification

This monograph summarizes recent developments in the purification and analysis of natural and recombinant proteins. The basic strategies employed in protein purification are reviewed with regards to the characteristics of the protein of interest that may aid its isolation, choice of the starting material, and use of denaturants. Preparation of cell-free extracts followed by bulk precipitation and/or phase partition constitute the initial steps of many purification schemes. Chromatographic methods (size exclusion, ion exchange, hydroxylapatite, reversed phase, hydrophobic interaction and affinity based) utilizing either traditional, low pressure or high-performance liquid chromatography instrumentation are discussed. Electrophoretic techniques used to analyze the homogeneity of the protein product include SDS-PAGE, isotachophoresis, IEF and two dimensional gel electrophoresis.

Interactions of human serum albumin with a modified poly(vinyl alcohol) gel packing for high-performance liquid chromatography

The interactions of human serum albumin (HSA) with a poly(vinyl alcohol) gel packing (Asahipak GS-520) for high-performance liquid chromatography of proteins were investigated. Under certain conditions, the elution of HSA from the GS-520 column was retarded and its chromatogram was split into two peaks, indicating weak adsorption of HSA onto the gels and also the existence of two subfractions, i.e. human mercapto-albumin (HMA) and human non-mercapto-albumin (HNA). The chromatograms were confirmed to be greatly influenced by the salt composition, the pH, and the temperature of the isocratic mobile phase. It is characteristic for the adsorption of HSA onto the gels to be suppressed at a pH near its isoelectric point. The HSA-gel interaction parameters calculated using an adsorption chromatography theory demonstrate that the adsorption of HSA is caused by enthalpy-driven interactions, which are depressed by lowering the pH, in addition to hydrophobic interactions. Under the recommended chromatographic conditions for high resolution of HMA/HNA, it was found that the HSA samples possessed some subfractions besides HMA and HNA fractions.

The use of dye-ligand affinity chromatography for the purification of non-enzymatic human plasma proteins

Literature data are analysed in this review on the use of immobilized triazine dyes for the characterization, isolation and purification of non-enzymatic human plasma proteins in both conventional and high-pressure liquid chromatography systems. Attention is focused on the mode of interaction between the dyes and these proteins, as well as on the advantages over previously reported techniques. Future developments are discussed.

Profiling of carbohydrates, glycoproteins and glycolipids

Current chromatographic methods for the analysis of a variety of carbohydrate materials in body fluids and tissues have been reviewed, from the viewpoints of clean-up of samples, separation modes, methods for detection and quantification, and degree of convenience. This review also contains several tables, listing names of samples, methods of analysis, analytical conditions, and normal as well as pathological levels reported, from representative publications.

Tumor cell autocrine motility factor

A cell motility-stimulating factor has been isolated, purified, and partially characterized from the serum-free conditioned medium of human A2058 melanoma cells. We term this activity "autocrine motility factor" (AMF). AMF has the properties of a protein with an estimated size of 55 kDa. At concentrations of 10 nM or less, AMF stimulated the random or directed motility of the producer cells. However, AMF is not an attractant for neutrophils. Amino acid analysis of the purified AMF protein revealed a high content of serine, glycine, glutamic acid, and aspartic acid residues. The activity of AMF was not replaced or blocked by known growth factors such as epidermal growth factor or type beta transforming growth factor. Mechanistic studies showed that AMF stimulated the incorporation of [3H]methyl into cell membrane phospholipids after incubation with [methyl-3H]methionine with a sustained increase in the methylation of phosphatidyldimethylethanolamine to phosphatidylcholine. In contrast, AMF did not affect the incorporation of [1,2-14C]choline into phosphatidylcholine. AMF was produced in large amounts by three different clones of ras oncogene-transfected metastatic NIH 3T3 cells but not by the nontransformed parental cells. AMF may play a major role in the local invasive behavior of tumor cells and may also facilitate the concerted invasion by groups of tumor cells.

Examinations of cerebrospinal fluid immunoglobulin G by chromatofocusing

IgG components in the CSF and paired sera were examined by chromatofocusing. The separations were performed using the FPLC system with a mono P column and were based on a pH gradient between 9.5 and 6.0. A total amount of 0.1 mg IgG was applied to the column. All samples with oligoclonal IgG were easily identified and the findings differed clearly from those of normal IgG. The sensitivity, resolution capacity and relatively fast as well as easy performance make chromatofocusing a promising tool for investigations of IgG in the CSF.