Showing papers on "Human serum albumin published in 1987"
TL;DR: A paramagnetic-labeled macromolecule, albumin-(Gd-DTPA), was prepared for use as an intravascular contrast agent for magnetic resonance imaging and covalently conjugated to human serum albumin through the bifunctional anhydride of DTPA.
Abstract: A paramagnetic-labeled macromolecule, albumin-(Gd-DTPA), was prepared for use as an intravascular contrast agent for magnetic resonance imaging. An average of 19 Gd-DTPA chelates were covalently conjugated to human serum albumin through the bifunctional anhydride of DTPA. The albumin-(Gd-DTPA) was characterized with use of high-performance liquid chromatography, sodium dodecyl sulfate gel electrophoresis, atomic absorption, biuret and Bradford protein tests, and by its effect on proton relaxation (relaxivity). The average molecular weight was 92,000 daltons, indicating the albumin conjugate was predominantly monomeric. The T1 relaxivity of albumin-(Gd-DTPA) was 273 mM-1 sec-1 relative to carrier concentration, which corresponds to a relaxivity of 14.9 mM-1 sec-1 relative to gadolinium concentration. The average conditional stability constant for albumin-bound Gd-DTPA chelate was log K = 20.0. Spin-echo images of rats demonstrated persistent enhancement of vascular tissues and slowly flowing blood. Application of albumin-(Gd-DTPA) may augment the MR assessments of blood volume, tissue perfusion, and flow characteristics.
280 citations
TL;DR: In spite of the slightly lower surface tension of siliconized glass, the extent of protein adsorption is slightly higher to Teflon than to siliconizedGlass, attributed to the theoretically well known phenomenon of "screening."
Abstract: Adsorption isotherms of four plasma proteins (fibrinogen, IgG, human serum albumin, and bovine serum albumin) using four different types of small particles as substrates (siliconized glass, Teflon, polyvinylchloride, and Nylon-6, 6) are reported. The suspending liquid medium was phosphate-buffered saline, with a surface tension higher than that of any of the proteins. In keeping with the thermodynamic expectations for these systems, protein adsorption decreases for all solids in sequence from fibrinogen (the most hydrophobic) to IgG, human serum albumin, and bovine serum albumin (the most hydrophilic). Furthermore, the extent of protein adsorption also decreases from the low surface tension (hydrophobic) to the higher surface tension solids, again as expected on thermodynamic grounds. There is one minor yet interesting exception to the thermodynamic pattern: In spite of the slightly lower surface tension of siliconized glass, the extent of protein adsorption is slightly higher to Teflon than to siliconized glass. This result is attributed to the theoretically well known phenomenon of “screening”.
248 citations
TL;DR: The sensitivity of surface plasmon resonance techniques to changes in local interfacial refractive index has been exploited to detect immuno-complex formation in two model biochemical systems and binding reactions could be followed with respect to time.
237 citations
TL;DR: Preliminary studies indicate that paramagnetically labeled macromolecules that distribute in the intravascular space may be effective for MR imaging evaluation of tissue blood volume.
Abstract: Albumin is a macromolecule that remains largely confined to the vascular space after intravenous administration. Human serum albumin was paramagnetically labeled by covalently binding from nine to 18 gadolinium-DTPA (diethylenetriaminepentaacetic acid) chelates per protein molecule. This conjugate was tested in varying doses for in vivo biodistribution and effectiveness in tissue relaxation. After intravenous injection of the agent in rats, T1 relaxation times were significantly reduced in samples of the blood and in lung, heart, spleen, kidney, and brain tissue. These effects persisted at a relatively constant level for the next 30 minutes. In vivo magnetic resonance imaging of the heart and lungs of rats and rabbits confirmed the prolonged contrast-enhancing effect of the labeled albumin. These preliminary studies indicate that paramagnetically labeled macromolecules that distribute in the intravascular space may be effective for MR imaging evaluation of tissue blood volume.
211 citations
TL;DR: Autoradiography results indicate that uniform distribution of T4 within tissues requires circulating thyroid hormone-binding proteins, and that the specific binding proteins are required to ensure nonfluctuating circulating concentrations of free T4 in vivo.
Abstract: We used autoradiography to test the hypothesis that a major function of thyroid hormone-binding proteins in plasma is to ensure uniform distribution of thyroid hormones among cells of a given tissue The distribution of [125I]T4 within rat hepatic lobules was determined after its single pass perfusion through the portal vein in solutions containing or lacking thyroid hormone-binding proteins These proteins included thyroid hormone-binding globulin, thyroid hormone-binding prealbumin, and albumin In the absence of these proteins, virtually all of the perfused T4 was taken up by the periportal cells, and subsequent perfusion with protein-free solution did not cause redistribution of this T4 In the presence of these proteins, in contrast, the perfused T4 was taken up uniformly by all cells within the lobule Albumin alone was sufficient to ensure uniform cellular uptake of T4 However, variation of oleic acid concentrations within the physiological range markedly influenced the concentration of free T4 in a solution of 4% human serum albumin, but not in human serum These results indicate that uniform distribution of T4 within tissues requires circulating thyroid hormone-binding proteins, and that the specific binding proteins, thyroid hormone-binding globulin and thyroid hormone-binding prealbumin, are required to ensure nonfluctuating circulating concentrations of free T4 in vivo Other hormone-binding proteins in plasma and some transport proteins may function similarly
137 citations
Journal Article•
TL;DR: Reaction of these reagents with proteins is pH independent, protein concentration dependent, and takes 5-60 min at mild pH (8.0) and temperature (25-37 degrees C), in yields up to 95% (corrected).
Abstract: Two fluorine-18-labeled reagents, methyl 3-(/sup 18/F)fluoro-5-nitrobenzimidate and 4-(/sup 18/F)fluorophenacyl bromide, have been prepared for covalent attachment of fluorine-18 to proteins. Both reagents can be prepared in moderate yields (30-50%, EOB) in synthesis times of 50-70 min. Reaction of these reagents with proteins (human serum albumin, human fibrinogen, and human immunoglobulin A) is pH independent, protein concentration dependent, and takes 5-60 min at mild pH (8.0) and temperature (25-37 degrees C), in yields up to 95% (corrected). The /sup 18/F-labeled proteins are purified by size exclusion chromatography.
112 citations
TL;DR: Results from pulse-labeling studies indicated that the bacterially produced HSA was secreted from cells which had been converted to protoplasts, providing further evidence that B. subtilis can translocate this foreign protein across the cell membrane.
Abstract: We have fused the structural gene (hsa) for human serum albumin (HSA) to the expression elements and signal sequence coding region of each of two genes from Bacillus amyloliquefaciens P, an alpha-amylase gene (amyBamP) and a neutral protease gene (nprBamP). Bacillus subtilis strains harboring either of these gene fusions synthesized a protein with the antigenic characteristics and size (68 kilodaltons) of HSA. Results from pulse-labeling studies indicated that the bacterially produced HSA was secreted from cells which had been converted to protoplasts. Results from similar studies with intact cells suggested that the signal sequence was removed from the hybrid protein, providing further evidence that B. subtilis can translocate this foreign protein across the cell membrane. Signal sequence removal was efficient when the level of HSA synthesis was low. However, in strains which synthesized HSA at a high level, signal sequence removal was less efficient.
106 citations
TL;DR: The results suggest that the antibodies of L‐DOPA and DA antisera recognize preferentially the catechol moiety, whereas for the anti‐NA and anti‐OA antibodies, the lateral chain is important.
Abstract: Antisera were raised against L-3,4-dihydroxyphe-nylalanine (L-DOPA), dopamine (DA), noradrenaline (NA), and octopamine (OA). This was achieved by coupling each molecule to bovine serum albumin or human serum albumin using glutaraldehyde. The conjugated aromatic amines were kept in a reducing medium containing sodium metabisulfite. Antiserum specificity was tested using an enzyme-linked immunosorbent assay method for catecholamines. Competition experiments were done between the immunogen coated on the well plates and each catechol-amine, either in the free state or in conjugated form, previously incubated with an antiserum. In each case, the non-conjugated compound was poorly recognized. The nonre-duced conjugates of L-DOPA and DA were well recognized, whereas those of NA and OA were poorly immunoreactive. The cross-reactivity ratios established in the competition experiments allowed the specificity of the immune response to be defined. In each case, it was found to be high. The results suggest that the antibodies of L-DOPA and DA antisera recognize preferentially the catechol moiety, whereas for the anti-NA and anti-OA antibodies, the lateral chain is important.
85 citations
TL;DR: The relationship between the lone tryptophan residue at position 214 and drug binding sites (Sites I and II) in human serum albumin (HSA) was studied by fluorescence energy transfer by Förster's equation.
78 citations
TL;DR: The extreme potency, excellent targeting, and apparent lack of toxicity of this agent suggest that MAM probably will have a clinical application in detecting focal hepatic and splenic lesions.
Abstract: A superparamagnetic MR contrast agent was synthesized by incorporating 150-250-A particles of magnetite (Fe3O4, Fe2O3) in 1-5 microns human serum albumin microspheres. Magnetite albumin microspheres (MAM) target almost exclusively to the reticuloendothelial system after IV administration, are stable in vitro and in vivo, and possess a long shelf life. The agent has a large magnetic susceptibility effect that selectively reduces T2 with little effect on T1. Biodistribution studies that use a dose of 20 mg MAM/kg show prompt clearance from the blood pool with marked decrease in T2 for rat liver (40%) and spleen (45%) with a small decrease in liver (5%) and spleen (10%) T1 values. Pulmonary T1 and T2 decrease transiently over the first 24 hr, while no significant changes were observed in other tissues. Imaging of a rabbit VX2 tumor model resulted in a 200% increase in the contrast ratio of VX2 tumor to normal liver on T2-weighted and mixed T1-/T2-weighted pulse sequences after administration of contrast agen...
70 citations
TL;DR: The recombinant HSA is produced essentially as an insoluble aggregate and differs from natural HSA by the presence of a methionine at the N-terminus, but the Met-HSA could be re-natured, purified and was found to be very similar to the natural protein.
Abstract: Significant synthesis of Human Serum Albumin (HSA) was demonstrated in E. coli using efficient bacterial expression signals. The recombinant HSA is produced essentially as an insoluble aggregate and differs from natural HSA by the presence of a methionine at the N-terminus. However, the Met-HSA could be re-natured, purified and was found to be very similar to the natural protein. A procedure was devised to produce mature HSA starting with the authentic N-terminal sequence from E. coli. By analogy with the maturation of the HSA propeptide, a plasmid expressing a fusion between the first six residues of the bacteriophage λcII protein (Val-Arg-Ala-Asn-Lys-Arg-) and the sequence of mature HSA was constructed. After renaturation, this fusion protein was cleaved by trypsin in vitro to yield a mature refolded HSA with native N-terminal sequence. This protein could not be distinguished by several criteria from authentic natural HSA.
TL;DR: Blatt et al. as discussed by the authors studied the protein concentration dependence of the acrylamide quenching of the fluorescence of the proteins, human serum albumin and monellin, and found no such dependence for the concentration range of 0.5-20 mg/ml.
TL;DR: The in vitro findings were confirmed by a pharmacokinetic study in volunteers given [14C] teicoplanin i.v., in whom the fraction of teioplanin bound to serum protein ranged between 87.6 and 90.8%.
Abstract: The interaction between the main components of the new glycopeptide antibiotic teicoplanin, A2–2, A2–3, A2–4, A2–5 and A3–1, and human serum albumin has been studied in vitro by equilibrium dialysis (pH 7.4, 37°C). From Scatchard analysis of the data, the calculated association constants (Ka) were: A2–2, 2.47×104, A2–3, 2.86×104, A2–4, 2.95×104 and A2–5, 3.87×104 mol·l−1. The number of binding sites per albumin molecule ranged between 1.23 to 1.31. A3–1 had a lower affinity with a Ka of about 5×103 mol·l−1. Extrapolated to the in vivo situation, the data suggested that about 90–95% of A2 components will be bound to serum albumin, and about 68–72% of A3–1. The in vitro findings were confirmed by a pharmacokinetic study in volunteers given [14C] teicoplanin i.v., in whom the fraction of teicoplanin bound to serum protein ranged between 87.6 and 90.8%.
TL;DR: There was very little difference in plasma binding in arthritic patients compared with normal subjects, and total protein and albumin concentrations in plasma compared with synovial fluid, but the albumin:total protein ratios were essentially the same.
TL;DR: The antibody response to a rabies vaccine doubly inactivated with 0.025% beta-propiolactone and 0.1% tri(n)butyl phosphate and stabilized with 2.5% human serum albumin completely inhibited IgE binding to solid-phase vaccine.
Abstract: We examined the antibody response to a rabies vaccine doubly inactivated with 0.025% beta-propiolactone and 0.1% tri(n)butyl phosphate and stabilized with 2.5% human serum albumin. Antibodies were measured by using the following four antigen preparations: complete doubly inactivated rabies vaccine, rabies vaccine inactivated only with tri(n)butyl phosphate, beta-propiolactone and human serum albumin, and human serum albumin alone. The fluid phase of the preparation of beta-propiolactone and human serum albumin completely inhibited IgE binding to solid-phase vaccine. Of 21 subjects with urticarial reactions to a booster, 19 had IgE to doubly inactivated vaccine and to beta-propiolactone and human serum albumin. None of 27 immunized subjects without urticaria had detectable IgE. In paired pre- and postimmunization sera, IgE appeared in six of seven of the subjects with urticaria and in one of seven nonreactors. These sera did not contain a significant level of IgE to singly inactivated vaccine or to human serum albumin alone.
TL;DR: The first step in the interaction between oxaprozin glucuronide and human serum albumin (HSA) is formation of a reversible complex which then leads to the following reactions; acyl migration of the aglycone from position 1 to positions 2, 3 and 4 of the glucuronic acid moiety; hydrolysis of the glycosidic bond; and covalent binding of oxaprzin to the HSA molecule.
Abstract: 1. The first step in the interaction between oxaprozin glucuronide and human serum albumin (HSA) is formation of a reversible complex which then leads to the following reactions; (a) acyl migration of the aglycone from position 1 to positions 2, 3 and 4 of the glucuronic acid moiety; (b) hydrolysis of the glycosidic bond; and (c) covalent binding of oxaprozin to the HSA molecule. The isomers of oxaprozin glucuronide formed in (a) and the covalently bonded drug in (c) are also hydrolyzed to oxaprozin.2. Oxaprozin and ligands known to bind at Site II as classified by Sudlow et al. (1976), also called the benzodiazepine binding site (Muller and Wollert 1975), inhibit these reactions with oxaprozin glucuronide, while ligands which are known to bind at other sites on HSA do not.3. Modification of a single tyrosine residue, located within Site II, with tetranitromethane, diisopropylfluorophosphate, and p-nitrophenylacetate causes significant reduction of the covalent binding of oxaprozin to HSA.4. Tetranitromet...
TL;DR: The results suggest that CMPF is a major interferent in the underestimation of the serum albumin concentration by the BCP method in uremia.
TL;DR: Results indicate that ceftriaxone may increase the risk of bilirubin encephalopathy in jaundiced premature infants and reduce the reserve albumin concentration in newborn serum.
Abstract: The effect of ceftriaxone on bilirubin-albumin binding was measured in vitro using the peroxidase method with human serum albumin and a dialysis rate method with adult and newborn serum. Ceftriaxone competes with bilirubin for binding to human serum albumin; the displacement constant is 1.5 X 10(4) L/mol. Therapeutic levels of ceftriaxone decrease the reserve albumin concentration in newborn serum by 39%. These results indicate that ceftriaxone may increase the risk of bilirubin encephalopathy in jaundiced premature infants.
Journal Article•
TL;DR: The data suggest that the albumin-catalyzed reaction of cis-4-OHCP in plasma represents an important pathway for the transformation of cyclophosphamide metabolites and further emphasize the importance of considering phosphoramide mustard generated extracellularly versus intracellularly and the respective contributions ofextracellular and intrace cellular phosphoramia mustard to cycloph phosphamide cytotoxicity in vivo.
Abstract: Cyclophosphamide, a widely used anticancer agent, requires initial metabolic activation to 4-hydroxycyclophosphamide (4-OHCP) to elicit its activity. The rate of decomposition of cis-4-OHCP was much faster in plasma than in buffer at pH 7.4. This plasma activity was not affected by treatment with acid (pH 1.3) or heat (60 degrees C for 30 min). The activity was retained in the macromolecular fraction (greater than 10,000) but not in the filtrate. Serum albumin was identified as the catalyst for the elimination step that generates phosphoramide mustard from aldophosphamide; albumin had no effect on the rate of ring opening of cis-4-OHCP to aldophosphamide. This catalytic activity was dependent on serum albumin concentration and independent of pH over the range of 6.5 to 7.5, in contrast to the buffer-catalyzed reaction. The catalytic rate constants kcat (pH 7.4, 37 degrees C) for phosphate buffer, human serum albumin, and bovine serum albumin were 1.13, 285, and 83 M-1 min-1, respectively. Pretreatment of cis-4-OHCP with serum albumin resulted in a time-dependent decrease in cytotoxic activity against L1210 tumor cells in vitro. These data suggest that the albumin-catalyzed reaction of cis-4-OHCP in plasma represents an important pathway for the transformation of cyclophosphamide metabolites and further emphasize the importance of considering phosphoramide mustard generated extracellularly versus intracellularly and the respective contributions of extracellular and intracellular phosphoramide mustard to cyclophosphamide cytotoxicity in vivo.
TL;DR: The thermodynamics of the binding of aromatic amino acids, i.e., tryptophan, phenylalanine and tyrosine to α-, β- and γ-cyclodextrin were investigated by microcalorimetry.
Abstract: The thermodynamics of the binding of aromatic amino acids, i.e., tryptophan, phenylalanine and tyrosine to α-, β- and γ-cyclodextrin were investigated by microcalorimetry. Heat was evolved following the interaction of tryptophan and tyrosine with α- and β-cyclodextrins but not with γ-cyclodextrin.Phenylalanine only appeared to react with γ-cyclodextrin. Human serum albumin contains these amino acids but the heat evolves following interaction with α and β-cyclodextrins was much lower than that evolved with the individual amino acids. No heat was evolved following the interaction of γ-cyclodextrin with the albumin.
TL;DR: Bound Hp again displays photophysical properties very similar with those of free Hp; however, the efficiency of Trp photo‐oxidation in HSA is about 5‐fold higher than in NATA owing to a limited rearrangement of the protein structure, induced by Hp binding, which enhances the probability of chemical quenching of O2(1Δg) by the indole ring.
Abstract: — The photosensitized oxidation of 10–100 μM N-acetyl-L-tryptophanamide (NATA) in neutral aqueous solution and in the presence of various dyes proceeds by a pure O2(1Δg)-involving mechanism. Incorporation of the tryptophyl (Trp) residue into the polypeptide chain of human serum albumin (HSA) has no influence on the mechanism and efficiency of Trp photooxidation when sensitized either by methylene blue, a non-binding dye, or by rose bengal, a dye that gives non-covalent 1: 1 complexes with HSA. This is due to the location of the Trp residue in close proximity of the protein surface and, in the case of rose bengal, to the coincidence of the photophysical properties (including the quantum yield of O2(1Δg) generation) for the free and HSA-bound dye. Hematoporphyrin also binds to HSA with 1: 1 stoichiometry, although at a different site from rose bengal. Bound Hp again displays photophysical properties very similar with those of free Hp; however, the efficiency of Trp photo-oxidation in HSA is about 5-fold higher than in NATA owing to a limited rearrangement of the protein structure, induced by Hp binding, which enhances the probability of chemical quenching of O2(1Δg) by the indole ring.
TL;DR: It has been demonstrated that adsorptive stripping voltammetry can be a useful technique for the study of the interaction of these two proteins directly in solution.
TL;DR: The structural changes in four genetic variants of human serum albumin were analyzed by tandem high-pressure liquid chromatography of the tryptic peptides, HPLC mapping and isoelectric focusing of the CNBr fragments, and amino acid sequence analysis of the purified peptides.
Abstract: The structural changes in four genetic variants of human serum albumin were analyzed by tandem high-pressure liquid chromatography (HPLC) of the tryptic peptides, HPLC mapping and isoelectric focusing of the CNBr fragments, and amino acid sequence analysis of the purified peptides. Lysine-372 of normal (common) albumin A was changed to glutamic acid both in albumin Naskapi, a widespread polymorphic variant of North American Indians, and in albumin Mersin found in Eti Turks. The two variants also exhibited anomalous migration in NaDodSO4/PAGE, which is attributed to a conformational change. The identity of albumins Naskapi and Mersin may have originated through descent from a common mid-Asiatic founder of the two migrating ethnic groups, or it may represent identical but independent mutations of the albumin gene. In albumin Adana, from Eti Turks, the substitution site was not identified but was localized to the region from positions 447 through 548. The substitution of aspartic acid-550 by glycine was found in albumin Mexico-2 from four individuals of the Pima tribe. Although only single-point substitutions have been found in these and in certain other genetic variants of human albumin, five differences exist in the amino acid sequences inferred from cDNA sequences by workers in three other laboratories. However, our results on albumin A and on 14 different genetic variants accord with the amino acid sequence of albumin deduced from the genomic sequence. The apparent amino acid substitutions inferred from comparison of individual cDNA sequences probably reflect artifacts in cloning or in cDNA sequence analysis rather than polymorphism of the coding sections of the albumin gene.
TL;DR: The results demonstrate the presence of specific binding sites for paf-acether in human platelets and the direct competition by BN 52021 for these sites and Serum albumin appears as a necessary phospholipid carrier for specific [3H]paf-ACether binding.
TL;DR: A detailed analysis of the reaction between the double-labelled acetaldehyde-albumin complexes and K562 cells revealed that the cytotoxic activity resulted from the release of acetaldehyde from such complexes and the preferential binding of the free acetaldehyde to the target cells.
TL;DR: Three equilibria models for the dimer binding were developed and tested and the data were found to fit best with a model proposing a single high‐affinity binding site for theDimer, independent of and different than the monomer site.
Abstract: Porphyrin binding to serum albumin was studied at the molecular level probing the effects of: porphyrin self-aggregation, porphyrin species, temperature and protein-bound fatty acids. Human serum albumin was found to have a single high-affinity site for porphyrin monomers, with binding constants of 2 x 106, 5 x 107 and 3 x 108 (37o C, neutral pH, M−1), for hemato-, deutero- and protoporphyrins, respectively. Three equilibria models for the dimer binding were developed and tested. The data were found to fit best with a model proposing a single high-affinity binding site for the dimer, independent of and different than the monomer site. The binding constants of the hematoporphyrin and deuteroporphyrin dimers to human serum albumin (37o C, neutral pH, M−l) being 4 x 10* and 5 x 108 respectively. The temperature dependence (Dp and HSA, 22-37o C) of the monomer binding showed the process to be entropy-driven (δGo= -45 kJ mol−1; δSo=+146 kJ mol−1; δHo= 0 kJ mol−1). For the dimer binding, the enthalpy change was found to be highly temperature-dependent implying continuous changes in the heat capacity of the system over the entire temperature range, the trend at the 37o C region fitting an entropy-driven process. The monomer vs dimer differences in temperature dependence strongly support separate and independent binding sites for these species. Similar thermodynamics were determined for fatty-acid carrying as well as for fatty-acid free HSA, with mild quantitative (but not qualitative) shifts.
TL;DR: The amino acid substitutions in three different types of proalbumins designated Gainesville, Taipei, and Takefu are identified and it is shown that each of the first two types has been identified in geographically separate, ethnically diverse populations and therefore must have arisen by independent mutations.
Abstract: Proalbumins are rare genetic variants of human serum albumin containing a basic propeptide that is not removed during post-transcriptional processing because of a mutation in the site of excision, an Arg-Arg sequence. We have identified the amino acid substitutions in three different types of proalbumins designated Gainesville, Taipei, and Takefu. The first two proalbumins are identical to previously described proalbumins of the Christchurch and Lille types, respectively, and exhibit the characteristic properties of susceptibility to tryptic cleavage and of lower metal-binding affinity. Takefu is a third type of proalbumin and resists tryptic cleavage because of the substitution Arg-1----Pro. Each of the first two types of proalbumins has been identified in geographically separate, ethnically diverse populations and therefore must have arisen by independent mutations. There is some tendency for mutations in albumin to cluster in the propeptide sequence. Although the substitution His3----Gln in the genetic variant albumin Nagasaki-3 decreases metal-binding affinity, mutations further down the polypeptide chain have no such effect, nor is there any reduction of copper-binding affinity in albumin from patients with Wilson disease.
Journal Article•
TL;DR: The separation of human α-fetoprotein from human serum albumin may improve and help maintain the accuracy of immunoassays for α- Fetoprotein, making the chromatography on immobilized Ni2+ a valuable diagnostic tool.
Abstract: We have explored immobilized metal affinity chromatography as a means of resolving α-fetoprotein from its homologous albumin, a problem perennially encountered in the purification of an α-fetoprotein or its detection.
Human α-fetoprotein and human serum albumin were chromatographed on immobilized iminodiacetic acid charged with either Co2+, Ni2+, Cu2+, or Zn2+. Neither human α-fetoprotein nor human serum albumin displayed any affinity for Co2+ and Zn2+. However, both proteins were bound to Cu2+ and were partially resolved by affinity elution with imidazole. By contrast, human α-fetoprotein and human serum albumin were completely resolved on immobilized Ni2+. Similar results were obtained using bovine α-fetoprotein and bovine serum albumin.
The resolution of an α-fetoprotein from serum albumin should aid the purification of α-fetoprotein from a biological fluid containing overwhelming quantities of albumin, for example, serum. Importantly, the separation of human α-fetoprotein from human serum albumin may improve and help maintain the accuracy of immunoassays for α-fetoprotein, making the chromatography on immobilized Ni2+ a valuable diagnostic tool.