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Biomedical subjects

E Sulkowski

Publications and source records attributed to E Sulkowski.

At least 19 recordsLinked to original sources
PubMed2001

Thiophilic interaction chromatography of prostate-specific antigen.

Prostate-specific antigen (PSA) protein and complexes of PSA with alpha1-antichymotrypsin (PSA-ACT) or alpha2-macroglobulin (PSA-A2M) prepared in vitro, have strong affinity for different thiophilic gels (T-gel). Free PSA, and these PSA complexes can be isolated due to their affinity for T-gels. The average recovery of PSA from several of the T-gels, based upon ELISA measurements, was 84 to 94%. The data suggest that T-gel affinity can be explored for the purification of free and complexed PSA from various biologic fluids.

Antibodies↗
PubMed1998

Alzheimer's beta-amyloid peptide: affinity for metal chelates.

Alzheimer's amyloid peptide, A beta(1-42) and its fragments, A beta(1-28) and A beta(1-16), were chromatographed on IDA-M(II) columns (M: Cu2+, Ni2+ and Zn2+). The retention of A beta(1-42) and its fragments on IDA-Cu(II) could not be reversed in decreasing a gradient of pH, from 7.0 to 4.0. All A beta peptides were recovered from IDA-Ni(II) columns in a decreasing pH gradient from 7.0 to 4.0, within the pH range from 5.6 to 5.1. A beta(1-42) peptide was strongly retained on IDA-Zn(II) at pH 4.0, but its A beta(1-28) and A beta(1-16) were only transiently retained on IDA-Zn(II) columns when applied at pH 6.1. We submit that histidine clusters, residing both in the Alzheimer's beta-amyloid peptide and in most of the APP/APLP superfamily of proteins, constitute high-affinity binding sites for immobilized metal chelates.

Alzheimer Disease↗
PubMed1992

Spontaneous conversion of PrPC to PrPSc.

Octa-repeats of prion proteins (PrP) contain histidine and tryptophan residues which are known to function as ligands for transition metals. It is proposed that the spontaneous conversion of the PrPC (cellular) isoform into PrPSc (scrapie) isoform may be triggered by the coordination of these metals.

Animals↗
PubMed1992

Evaluation of the interaction of protein alpha-amino groups with M(II) by immobilized metal ion affinity chromatography.

The adsorption properties of various peptides and proteins, lacking histidyl groups, on immobilized Cu(II), Ni(II), Zn(II) and Co(II) ions are described; at pH 6 and below they were little retarded. At higher pH the retention became pronounced for iminodiacetate (IDA)-Cu(II) gel. This effect seems to be related to the presence of a terminal alpha-amino group; in the absence of this group the retention of the protein was largely eliminated. At pH 8.5 a terminal alpha-amino group is adsorbed as strongly as a histidyl group. IDA-Ni(II), IDA-Zn(II) and IDA-Co(II) gels display little or no attraction for the terminal alpha-amino group of a protein.

Amino Acid Sequence↗
PubMed1991

Surface topography of histidine residues in lysozymes.

Several avian and mammalian c-type lysozymes were chromatographed on chelated (to iminodiacetate) and immobilized transition metal ions (Co2+, Ni2+, Cu2+ and Zn2+) under a variety of experimental conditions. The varied affinity of evolutionary variants of the lysozyme family for chelated metal ions, IDA-M(II), can be rationalized primarily in terms of the presence, multiplicity and microenvironments of histidine residues. The chromatographic resolution of some of these closely related proteins attests to the analytical power of immobilized metal-ion affinity chromatography.

Animals↗
PubMed1991

Immobilized metal ion affinity chromatography of serum albumins.

The interaction of several serum albumins with chelated (iminodiacetate, IDA) and immobilized (agarose-IDA) metal ions, Co2+, Ni2+, Cu2+ and Zn2+, was studied. There was no retention of human, bovine, porcine, murine and avian albumins on IDA-Zn(II) and IDA-Co(II) columns. However, all albumins studied, i.e., those of: man, cow, pig, dog, rabbit, rat, mouse, chicken and pigeon were retained on IDA-Cu(II) columns, and all except dog albumin were retained also on IDA-Ni(II). The recognition of albumins by chelated and immobilized transition metals seems to be related to an affinity for the imidazole side chains. It is postulated that one to three imidazoles is involved in this interaction, under the employed experimental conditions (pH 7.0; 1 M sodium chloride). There is no evidence for any significant contribution of tryptophan or cysteine (Cys 34) residues to the chromatographic event. The retention of defatted albumin and albumin oligomers (human), on IDA-Cu(II) columns was not significantly different from that of non-defatted albumin or albumin monomer, respectively.

Animals↗
PubMed1989

The saga of IMAC and MIT.

Immobilized Metal-ion Affinity Chromatography, IMAC, has been gaining in popularity as the purification technique of choice for proteins and peptides. IMAC of proteins on transition metals (Co, Ni, Cu, Zn) can be rationalized in terms of the coordination of histidine residues. Brief accounts of the principles of IMAC, its anticipated development and plausible applications are presented. Metal Ion Transfer, MIT, may offer an efficient means to deplete a metal ion from a metalloprotein or, conversely, to charge its apo form with a metal.

Chromatography, Affinity↗
PubMed1989

Surface topography of histidine residues: a facile probe by immobilized metal ion affinity chromatography.

Immobilized metal ion affinity chromatography (IMAC) has been explored as a probe into the topography of histidyl residues of a protein molecule. An evaluation of the chromatographic behavior of selected model proteins--thioredoxin, ubiquitin, calmodulin, lysozyme, cytochrome c, and myoglobin on immobilized transition metal ions (Co2+, Ni2+, Cu2+, and Zn2+)--allows establishment of the following facets of the histidyl side chain distribution: (i) either interior or surface; (ii) when localized on the surface, accessible or unaccessible for coordination; (iii) single or multiple; (iv) when multiple, either distant or vicinal. Moreover, proteins displaying single histidyl side chains on their surfaces may, in some instances, be resolved by IMAC; apparently, the microenvironments of histidyl residues are sufficiently diverse to result in different affinities for the immobilized metal ions. IMAC, previously introduced as an approach to the fractionation of proteins, has become also, upon closer examination, a facile probe into the topography of histidyl residues. This is possible because of the inherent versatility of IMAC; an appropriate metal ion (M2+) can be selected to suit the analytical purpose and a particular chromatographic protocol can be applied (isocratic pH, falling pH, and imidazole elution).

Calmodulin↗
PubMed1989

Glass ampules and associated hazards.

Accessing drugs dispensed in glass ampules is always associated with glass fragment contamination of the ampule contents on opening. In this study, the glass fragment contamination from the external surface of the ampule occurred 60% of the time with 1-ml sized ampules (p less than .01). Glass contamination has been shown to increase with larger ampule size. The glass ampule poses a potential source of microbial infection to the patient, as well as other hazards to the user. Increased precautions and improved drug container design appear to be desirable.

Drug Contamination↗
PubMed1987

Facile resolution of alpha-fetoproteins and serum albumins by immobilized metal affinity chromatography.

We have explored immobilized metal affinity chromatography as a means of resolving alpha-fetoprotein from its homologous albumin, a problem perennially encountered in the purification of an alpha-fetoprotein or its detection. Human alpha-fetoprotein and human serum albumin were chromatographed on immobilized iminodiacetic acid charged with either Co2+, Ni2+, Cu2+, or Zn2+. Neither human alpha-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 alpha-fetoprotein and human serum albumin were completely resolved on immobilized Ni2+. Similar results were obtained using bovine alpha-fetoprotein and bovine serum albumin. The resolution of an alpha-fetoprotein from serum albumin should aid the purification of alpha-fetoprotein from a biological fluid containing overwhelming quantities of albumin, for example, serum. Importantly, the separation of human alpha-fetoprotein from human serum albumin may improve and help maintain the accuracy of immunoassays for alpha-fetoprotein, making the chromatography on immobilized Ni2+ a valuable diagnostic tool.

Chromatography, Affinity↗
PubMed1986

Improved large scale purification procedure of natural human fibroblast interferon.

Human fibroblast interferon, produced in tissue culture by a superinduction procedure, was purified 10,000-fold by chromatography to ca 50% purity as judged by SDS-PAGE. The specific activity of the interferon preparation is 2 X 10(8) and the yield is 70%. The interferon preparation is suitable for clinical use.

Chromatography, Affinity↗
PubMed1985

Purification of human urinary erythropoietin on controlled-pore glass and silicic acid.

Erythropoietin (Epo) has been isolated from raw human urine of anemic patients by controlled-pore glass and silicic acid chromatography. A purification factor of not less than 100-fold and recovery of about 80% of activity was routinely achieved. The resulting Epo preparation is active both in vivo and in vitro and can be neutralized by an antibody to human Epo indicating the native state and identity of the isolated Epo molecule. The preparation is stable at near neutral pH and is amenable to further purification.

Animals↗
PubMed1982

Adsorption of human alpha (leukocyte) interferon on glass: contributions of electrostatic and hydrophobic forces.

Human leukocyte-derived interferon (HuIFN-alpha) can be displaced from controlled-pore glass (CPG) with alkylamines at 0.1-0.3 M concentration. The eluting power of an alkylamine correlates positively with the extent of its alkylation: CH3NH3 + less than (CH3)2NH2 + less than (CH3)3NH+ less than (CH3)4N+. Interferon can also be recovered using an electrolyte and ethylene glycol as cosolvents. Apparently, both hydrophobic and electrostatic forces are involved in the adsorption of HuIFN-alpha to CPG.

Adsorption↗
PubMed1981

Chromatography of human leukocyte interferon on controlled pore glass.

Human leukocyte interferon (HuIFN-alpha ) was adsorbed on controlled pore glass (CPG) beads in 0.01 M potassium phosphate, pH 7.2. Partial recovery fo HuIFN-alpha from CPG, ranging from 50% to 75%, was obtained with ethylene glycol (6.8 M), ammonium chloride (1.0 M) and Tris.HCl (1.0 M). A near complete recovery (90%) was obtained with potassium phosphate (1 M), but there was no selectivity in the elution vis á vis other proteins. An efficient elution of HuIFN-alpha was accomplished with tetramethyl-, and tetraethylammonium chlorides: the recovery of HuIFN-alpha was complete at low concentrations (0.25 M to 0.50 M) of these salts at pH 8.0 and the elution of interferon was more selective than with other eluants.

Ammonium Chloride↗
PubMed1981

Partial purification and characterization of Syrian hamster interferon.

Syrian golden hamster interferon was made by stimulating secondary or benzo(a)pyrene-transformed embryo cells with Newcastle disease virus. Titres of 1000 to 6000 units/ml of tissue culture fluid were obtained. The ionic properties of this interferon were characterized by chromatography on cation and anion exchangers and also by isoelectric focusing when two components were observed: a major component, pI 5.8 and a minor component, pI 6.6. Hamster interferon was partially purified on a tandem of sorbents of diverse chromatographic bias: anion exchanger lead to metal chelate lead to hydrophobic ligand. The purified preparation had a specific activity of about 1 X 10(6) units/mg protein; the recovery of activity was nearly complete. The apparent mol. wt. of hamster interferon, as estimated by SDS-polyacrylamide gel electrophoresis under non-reducing conditions, is 17000. Crude Syrian hamster interferon preparations had some activity on mouse cells; this heterologous activity was entirely due to a small subpopulation of interferon molecules which could be isolated on phenylagarose.

Animals↗
PubMed1980

Glycosylation of human leukocyte interferon: effects of tunicamycin.

Antiviral activity of interferon secreted by human leukocytes into the culture fluid in the presence of tunicamycin (1-2 microgram/ml) was significantly decreased, by 50-60 percent, in comparison to that produced in the absence of the antibiotic. No loss in antiviral activity occurred when tunicamycin was added to already harvested interferon preparations. Some physico-chemical and biological properties of human leukocyte interferon synthesized in the presence of tunicamycin (HL-IFT) were apparently altered by comparison with those of control preparations of human leukocyte interferon (HL-IF): HF-IFT had only one molecular weight component of 16,000 daltons in contrast to the two components of HL-IF of 16,000 and 21,000 daltons. HL-IFT also had a higher apparent hydrophobicity and was less efficiently neutralized by an antibody raised against HL-IF. However, some other properties remained unchanged: isoelectric point, pI about 6; affinity for immobilized polyriboinosinic acid and a spectrum of cross-species antiviral activity. These data support the notion that the major component of HL-IF (70%, 16,000 daltons) is apparently nonglycosylated whereas the minor component (30%, 21,000 daltons) is glycosylated via saccharide-lipid intermediates.

Antigens↗