Purification of human fibroblast interferon by zinc chelate affinity chromatography

Immobilized palladium(II) ion affinity chromatography for recovery of recombinant proteins with peptide tags containing histidine and cysteine

Fusion of peptide-based tags to recombinant proteins is currently one of the most used tools for protein production. Also, immobilized metal ion affinity chromatography (IMAC) has a huge application in protein purification, especially in research labs. The combination of expression systems of recombinant tagged proteins with this robust chromatographic system has become an efficient and rapid tool to produce milligram-range amounts of proteins. IMAC-Ni(II) columns have become the natural partners of 6xHis-tagged proteins. The Ni(II) ion is considered as the best compromise of selectivity and affinity for purification of a recombinant His-tagged protein. The palladium(II) ion is also able to bind to side chains of amino acids and form ternary complexes with iminodiacetic acid and free amino acids and other sulfur-containing molecules. In this work, we evaluated two different cysteine- and histidine-containing six amino acid tags linked to the N-terminal group of green fluorescent protein (GFP) and studied the adsorption and elution conditions using novel eluents. Both cysteine-containing tagged GFPs were able to bind to IMAC-Pd(II) matrices and eluted successfully using a low concentration of thiourea solution. The IMAC-Ni(II) system reaches less than 20% recovery of the cysteine-containing tagged GFP from a crude homogenate of recombinant Escherichia coli, meanwhile the IMAC-Pd(II) yields a recovery of 45% with a purification factor of 13.

Preparation of an iminodiacetic acid-modified capillary and its performance in capillary liquid chromatography and immobilized metal chelate affinity capillary electrophoresis

We prepared iminodiacetic acid (IDA)-modified and Cu(II)-IDA-modified capillaries through polymerization of N-(vinylbenzylimino) diacetic acid. The fundamental performance of these capillaries was examined in capillary liquid chromatography (LC) and immobilized metal chelate affinity capillary electrophoresis (IMACE). Copper(II), cobalt(II), and hematin were detected at different retention times by means of capillary LC with a chemiluminescence detector, during which the IDA-modified capillary was used. The difference in the retention times was attributed to the difference in the interaction between metal ions or complex and IDA moieties on the inner wall of the capillary. In addition, human serum albumin (HSA) and human serum gamma-globulin (HgammaG) were separated and detected using IMACE with an absorption detector, during which the Cu(II)-IDA-modified capillary was used. The separation of HSA and HgammaG was achieved through the interaction between proteins and Cu(II) chelate moieties on the inner wall of this capillary.

Liver targeting of human interferon-beta with pullulan based on metal coordination

Although interferon (IFN)-beta is widely used for the elimination of hepatitis C virus in patients with chronic liver disease, its clinical efficacy is unsatisfactory. Targeting IFN-beta to the liver might enhance its efficacy without increasing its side effects. The objective of the present study was to target IFN-beta to the liver to enhance its biological activity and reduce its side effects. A chelating residue, diethylenetriaminepentaacetic acid (DTPA), was introduced to pullulan, a water-soluble polysaccharide with a high affinity to the liver (DTPA-pullulan) and natural human IFN-beta was coordinately conjugated with the DTPA-pullulan by mixing in an aqueous solution containing zinc ions (Zn(2+)). Intravenous injection of the IFN-beta-DTPA-pullulan conjugate with Zn(2+) coordination into mice enhanced induction of an antiviral enzyme, 2',5'-oligoadenylate synthetase (2-5AS), specifically in the liver to a significantly greater extent than free natural IFN-beta. The enhanced 2-5AS level in the liver depended on the molar mixing ratio of IFN-beta, DTPA residue of the DTPA-pullulan, and Zn(2+). Moreover, the duration of the liver 2-5AS induction by the IFN-beta-DTPA-pullulan conjugate was longer than that by free natural IFN-beta. Thus, human IFN-beta-DTPA-pullulan conjugate appears to be applicable for clinical use, which is promising for treatment of patients with chronic hepatitis C.

A novel purification method for histidine-tagged proteins containing a thrombin cleavage site

A general procedure for the purification of histidine-tagged proteins has been developed using immobilized metal-ion affinity chromatography. This two-step purification method can be used for proteins containing a hexahistidine tag and a thrombin cleavage site, yielding high amounts of purified protein. The advantage of this method is that thrombin is used instead of imidazole in the final purification step. Imidazole can influence NMR experiments, competition studies, or crystallographic trials, and the presence of imidazole often results in protein aggregates. Removal of the His-tag results in a form of the protein of interest in which no additional tags are present, resembling the native form of the protein, with only three additional amino acids at the N-terminal side. Our method is compared with a more conventional method for the purification of the Azotobacter vinelandii NIFL PAS domain, overexpressed in Escherichia coli. It also proves to be successful for three different His-tagged proteins, the Klebsiella pneumoniae NTRC protein, and the A. vinelandii NIFA and NIFL proteins, and therefore it is a general method for the purification of His-tagged proteins.

Immobilized iminodiacetic acid (IDA)-type Cu2+ -chelating membrane affinity chromatography for purification of bovine liver catalase

A metal ion chelating membrane medium based on iminodiacetate-substituted modified short cotton cellulose was examined for the purification of bovine liver catalase (BLC). The effect of buffer pH, chelator surface density, initial concentration of crude enzyme and flow rate on BLC binding efficiency to the copper ion chelating membrane adsorbent were examined. Under the chromatographic conditions chosen, 67.7% recovery of BLC was attained with an overall 4.2-fold increase in specific activity in a single step. After performance of BLC purification, the chelating membrane adsorbent can be easily regenerated by imidazole or EDTA buffer with higher reviving effectiveness with the latter.

Purification of an atypical bovine interferon induced in response to heat shock in bovine cultured cells. Characterization in comparison with the classical alpha, beta and gamma interferon

Heat-shock induced factor (HSIF) was excreted by bovine MDBK cells during their recovery period after a heat shock. This factor has the capacity to induce 2',5' oligoadenylate synthetase activity, an enzyme generally by interferon treatment (J Biol Chem (1987) 262, 4806-4811). We have observed that an antiviral state was also produced in response to heat shock. HSIF was purified 10,000-fold and different techniques showed a copurification of both activities. Certain properties of HSIF were established, such as its molecular mass (45 kDa) and isoelectric point (6.8). This cytokine was acid-sensitive as IFN gamma (type II) and temperature labile contrarily to alpha, beta and gamma bovine IFN. Immunoprecipitation and comparative chromatography on lectines or polynucleotides established that HSIF was structurally different from the three classes of bovine IFN. Moreover, two-dimensional electrophoresis and comparative analysis of [35S] methionine-labeled proteins induced by HSIF alpha, beta or gamma bovine IFN showed that HSIF induces a specific set of proteins. Taken together, all these results strongly suggest that HSIF is a new atypical bovine interferon induced in response to heat shock.

Interaction of bovine estrogen receptor with immobilized zinc

The metal-binding properties of partially purified untransformed or salt-dissociated bovine estrogen receptors were studied using zinc-chelated iminodiacetic acid gels. Only the salt-dissociated 5S receptor is retained by the metal-chelated resin, and this interaction is dependent on the presence of dithiothreitol. The untransformed 9S receptor is not retained, indicating that the zinc-interacting amino acid residues may be masked by receptor-associated proteins such as 90K heat-shock protein or because of an unfavorable receptor conformation.

Purification of carboxypeptidase B by zinc chelate chromatography

A method is described to purify pancreatic carboxypeptidases B (CPB), removing contaminating endoproteinases that interfere with use of CPB for carboxy-terminal analysis or modification of proteins. The separation uses zinc chelate chromatography and is based on the property that CPB has higher affinity for immobilized zinc ions than do serine proteinases such as trypsin and chymotrypsin, which are abundant endoproteolytic activities in pancreas. CPB preparations are loaded onto a column of iminodiacetic acid-Sepharose that has been saturated with ZnCl2. A step gradient with buffers of decreasing pH is used to elute bound proteins. CPB elutes at a lower pH than do the serine proteinases.

Metal chelate affinity chromatography of Zn2+-inhibited protein Tyr(P) phosphatases

Metal chelate affinity chromatography using Zn2+-iminodiacetate agarose is shown to provide quantitative recoveries of Zn2+-inhibited protein Tyr(P) phosphatases. To elute adsorbed enzymes from immobilized Zn2+ three methods were compared: (1) removal of Zn2+ with chelators such as EDTA, (2) introduction of ligands to compete with enzyme for Zn2+ and (3) lowering pH to protonate sidechains in the enzyme that serve as ligands to Zn2+. Results show highest yields but poor purification for method 1, high purification but poor yields of active enzyme for method 3. It is concluded that gradients of competing Zn2+ ligands, such as imidazole, provide the best strategy for the purification of enzymes with retention of activity using metal chelate affinity chromatography.

Mechanical responses of rat vascular smooth muscle cells to rat interferon

Mechanical responses elicited by rat interferon (IFN) were investigated in rat vascular smooth muscle cells (RVSMC) in primary culture. IFN induced a dose-dependent reduction in the apparent cell surface area, which was quantitatively comparable to, or even greater than, the response elicited by the alpha-adrenergic agent, phenylephrine. Neither mock-IFN nor rat IFN-neutralized with specific antibodies elicited such a response. The sensitivity of RVSMC to the mechanical effect of IFN was species specific. In addition, the effect of IFN was inhibited by the Ca2+ entry blocker, verapamil.

Metal chelate-interaction chromatography of proteins with iminodiacetic acid-bonded stationary phases on silica support

An iminodiacetic acid (IDA)-bonded stationary phase on a wide-pore microparticulate silica support was used for the chromatography of amino acids and proteins at pH 5.0 and 6.0. Without chelated metal the retention behavior of the stationary phase parallelled that of other silica-bound cation exchangers used in high-performance liquid chromatography of proteins. In metal chelate-interaction chromatography (MCIC) with IDA, chelated by Cu(II), Zn(II), Ni(II), Fe(II), or Fe(III), amino acids were most strongly retained on Cu(II)-IDA, whereas all metal chelates separated the proteins under investigation but with different selectivity. The effect of salt concentration in the eluent on protein retention was investigated and the pertinent electrostatic and hydrophobic interaction parameters were evaluated. The proteins were separated by MCIC with increasing salt gradient and, using the same column, by hydrophobic-interaction chromatography with decreasing salt gradient. In MCIC the addition of methanol to the mobile phase had disparate effect on protein retention, whereas addition of histidine or glycine, which acted as competing ligands, reduced the retention.

Interferon-beta in patients with low-grade astrocytomas--a phase I study

In 3 patients with low-grade astrocytomas clinical pharmacology of interferon-beta (10(7) U/mg protein) was investigated. Interferon-beta with escalating dosage (2.3, 6.9, 23, 69 X 10(6) U/patient) was given to each patient in 4 infusions at weekly time intervals. In these patients dose-dependent plasma-levels of interferon-beta of up to 5800 IU/ml were achieved. Plasma concentrations showed a biphasic decline (T1 1/2:0.095-0.49 hrs and T2 1/2: 5-14.5 hrs). Side effects were: mild fatigue, myalgia, tachycardia, hypertension, and fever; the latter was well controlled by pretreatment application of paracetamol. Hematological changes included lymphopenia (2-6 hrs after infusion) and granulocytosis (3-6 hrs after infusion). Natural Killer cell activity was also monitored: 6 hours after infusion a drop of activity - not clearly dose dependent - was observed to a minimum of 1% pretreatment activity; 24 hrs after infusion activity increased up to a maximum of 400%. In this phase I study high biological activity of interferon-beta could be detected in plasma of astrocytoma patients - clinical tolerance was good and only mild toxicity was observed.

Purification of chick interferon by zinc chelate affinity chromatography and sodium dodecylsulfate-polyacrylamide gel electrophoresis

An improved purification method for chick interferon from the allantoic fluid of embryonated chick eggs is described. Interferon prepurified by perchloric acid treatment, zinc acetate precipitation, and chromatography on SP-Sephadex C-25 was further enriched by column chromatography on zinc chelate. Analysis on sodium dodecylsulfate polyacrylamide gel electrophoresis of the interferon preparation with a specific activity of 8 X 10(5) units/mg protein shows that the major antiviral activity migrated in a broad band in the range of 20-29 kD molecular weight. Several protein bands were stainable with Coomassie blue and silver nitrate in this molecular weight range. Between 80 and 95% of the total protein charged to the gel could be removed from the interferon containing fractions by sodium dodecylsulfate polyacrylamide gel electrophoresis.

Fractionation of human serum proteins by immobilized metal affinity chromatography

Human serum was fractionated on zinc and cadmium iminodiacetate and tris(carboxymethyl)ethylenediamine chelates. Zinc iminodiacetate was found to be useful in the isolation of hemopexin and alpha 2-macroglobulin. The chromatographic behaviour of serum proteins on zinc iminodiacetate could be modulated by the nature of the eluent; a sulphate-containing solvent increased the binding of serum proteins to immobilized metal ions.

Post-translational heterogeneity of the human vitamin D-binding protein (group-specific component)

The vitamin D-binding protein in human serum (the group-specific component) is an alpha 2-globulin which is genetically polymorphic in all populations studied. Previous work (J. Svasti and B. H. Bowman (1978) J. Biol. Chem. 253, 5188-5194, and J. Svasti, A. Kurosky, A. Bennett, and B. H. Bowman (1979) Biochemistry 18, 1611-1617) has shown that the electrophoretic variations of the proteins controlled by two allelic genes, Gc1 and Gc2, are due to at least three amino acid substitutions between Gc1 and Gc2 (Svasti et al. (1979] and to heterogeneity in the Gc1 phenotype arising from carbohydrate dissimilarities. Gc1 migrates electrophoretically as two protein bands, while Gc2 migrates cathodally as a single band. This study demonstrates a post-translational glycosylation difference occurring in a single area of the Gc1 sequence which accounts for the heterogeneity observed previously. The glycosylation site, a threonine residue, appears to be in a sequence which differs between Gc1 and Gc2. The O-glycosidic bond, which is typical of mucins, is rare in plasma proteins. The cyanogen bromide fragment containing the galactosamine-containing carbohydrate in Gc1 was partially sequenced through 20 residues from the amino terminus. No detectable galactosamine could be found in the homologous cyanogen bromide fragment in Gc2. A new purification procedure for the vitamin D-binding protein in human plasma has been developed. Three chromatographic steps provide purified protein.

Production and purification of human MG63 cell interferon

MG63 cells induced by Sendai virus were a convenient source of human interferon, which was of the beta type in antigenicity. When analyzed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE), the interferon migrated as a single component with a molecular weight of 22,000 daltons. It was purified to apparent homogeneity by chromatography on Blue Sepharose, followed by SDS-PAGE, and estimated to have a specific activity of 4 x 10(8) international units/mg of protein.

Immobilized metal ion affinity adsorption and immobilized metal ion affinity chromatography of biomaterials. Serum protein affinities for gel-immobilized iron and nickel ions

Immobilized metal ion affinity adsorption (IMA adsorption) is a collective term that is proposed to include all kinds of adsorptions whereby metal atoms or ions immobilized on a polymer cause or dominate the interaction at the sorption sites. IMA chromatography is one of the most powerful methods available to date for protein fractionation although this is not as yet widely recognized. This study deals with the theoretical aspects of IMA adsorption and its practical applications as exemplified by the various results reported here. The synthesis of iminodiacetate-substituted agarose (IDA-agarose) and tris(carboxymethyl)ethylenediamine-agarose (TED-agarose) is described. Many types of metal ions can easily be immobilized on these gel derivatives to form IMA adsorbents. We have not observed any damage to the proteins during the adsorption-desorption process. After performance of an experiment, the gels can easily be regenerated and can be loaded with the same or a different metal ion for an ensuing experiment. Specific adsorption is demonstrated for serum proteins on immobilized Ni(II) and Fe(III). Ligand-specific desorption (affinity elution) is also demonstrated by including in the buffer system certain solutes which are similar to or identical with some particular amino acids found in proteins. High concentrations of certain salts that affect the structure of water, such as Na2SO4, promote coordinate covalent bonding of proteins by a mechanism that is apparently similar to that found in hydrophobic interactions. Neutral detergents and aquoorganic solvents may be used. This opens up the possibility for the fractionation of membrane components. The IMA-adsorption method could also be expanded to other areas besides protein fractionation.

Affinity chromatography of primary human amnion interferon

The chromatographic behavior of human amniotic interferon on various affinity chromatography ligands was studied. Most of this interferon bound strongly to bovine plasma albumin-agarose, cibacron blue F3GA-agarose, concanavalin A-agarose and L-tryptophyl-L-tyrosine-omega-carboxyl-pentyl-agarose. After binding most of the interferon activity was eluted only with 50 percent ethylene glycol, showing the high hydrophobicity of this interferon. Smaller quantities could be recovered after phosphate-buffered saline elution or with increased salt concentration. On BPA-omega-carboxy-pentyl-agarose and omega-amino-hexyl-agarose, the majority of the biological activity was found in the break-through fraction (eluted with phosphate buffered saline) while some interferon was displaced with high salt or ethylene glycol. Increasing the salt concentration and lowering the pH was necessary to elute interferon from zinc chelate-agarose. These patterns indicate that human amniotic interferon is similar to human fibroblast (beta) interferon but different from human leukocyte (alpha) interferon. However, the heterogeneity displayed by amniotic interferon on bovine plasma albumin-agarose requires further investigation.

Pharmacokinetics of human interferon-beta in monkeys

Human fibroblast-derived interferon (HuIFN-beta) was administered to cynomolgus monkeys i.m. (2 x 10(5) iu/kg), i.v. (2 x 10(5) iu/kg) or intrathecally (3 x 10(5) iu/monkey) or given by a 3 hr i.v. infusion (2 x 10(5) iu/kg). One hr after intrathecal administration, interferon titers in the CSF were 1000-2000 iu/ml, and declined to less than 10 iu/ml during the first 24 hr. At the same time only minute amounts of HuIFN-beta were found in the sera of these animals. After i.m. administration, 5 iu/ml were found on average in the serum during the first 8 hr, with no interferon titer ever exceeding 10 iu/ml. No antiviral activity was found 24 hr after HuIFN-beta injection. HuIFN-beta injected i.v. resulted in serum interferon titers of approx. 300 iu/ml 30 min after administration, which then decreased to about 5 iu/ml during the first 8 hr 24 hr after injection no antiviral activity was detectable. Daily HuIFN-beta i.v. administrations over a period of four days did not affect the interferon clearance from the circulation. During HuIFN-beta infusion, constant HuIFN-beta titers of about 80 iu/ml were observed which then decreased during the following 5 hr to 2 iu/ml. The choice between a single i.v. injection, resulting in high serum titers for a few minutes, and a 3 hr infusion, resulting in an about fourfold lower but constant interferon level for over two hr, will depend on the mechanism of interferon action in vivo and on the question as to whether side effects can be diminished by infusion.

Effect of interferon on multiplication of avian sarcoma virus B77 in duck embryo fibroblasts

The effect of interferon on the multiplication of the avian sarcoma virus B77 in duck embryo fibroblasts was studied. The interferon used for this purpose as induced in duck embryo fibroblasts by high multiplicities of reovirus serotype 3 (strain Dearing) and purified to a specific activity of at least 2 x 10(7) units/ml (estimated to be at least 10% pure). Treatment of duck embryo fibroblasts transformed with B77 virus with as little as 50 units/ml of this interferon caused a rapid inhibition of the release of virus particles, and a decrease in the specific infectivity of the virus particles that were released of about six-fold. The protein composition of virus particles released from normal and interferon-treated duck embryo fibroblasts was not detectably different. Examination of the nature of the virus-specified proteins, as determined by precipitation with specific antisera, synthesized at various times after treatment of transformed duck embryo fibroblasts with 300 units/ml of interferon revealed the following major changes: i. a more than 5-fold increase in the amount of a protein with a molecular weight of about 100,000 (P100) precipitated by antiserum to reverse transcriptase. This increase was paralleled by a decrease in the amount of the gag-pol precursors Pr190 and Pr180, but the amount of the alpha and beta subunits of reverse transcriptase was not altered by interferon treatment. ii. An at last 3-fold increase in the amount of cell-associated gag proteins. iii. A two- to ten-fold decrease in the amount of a protein with an apparent molecular weight of 76,000, in all likelihood Pr76, precipitated by antiserum to gp85. The primary cause of the interferon-induced inhibition of virus particle release appears to be inability of Pr76 to associate with gPr95/gp85 in plasma cell membranes.

Purification of nucleosidediphosphatase of rat liver by metal-chelate affinity chromatography

A procedure is presented for the purification of nucleosidediphosphatase (nucleosidediphosphate phosphohydrolase, EC 3.6.1.6) of rat liver by affinity chromatography using metal conjugated to epoxy-activated Sepharose 6B. The enzyme is eluted from the conjugate by a solution of L-histidine. The enzyme, when bound to metal-chelate gel, is active in a suspended form, suggesting that the catalytic site is different from the site that binds to the metal-chelate gels. Substrate specificity and Km value of the enzyme obtained are similar to those of the enzyme obtained from the same sources by a conventional procedure, indicating that the metal-chelate affinity chromatography does not bring about any substantial change in the catalytic properties.

Metal chelate affinity chromatography. I. Influence of various parameters on the retention of nucleotides and related compounds

The influence of various parameters, such as pH, ionic strength and temperature, on the retention of different nucleotides and related compounds on copper chelate gels has been investigated in order to understand the respective roles played by the different solute constituents (i.e., heterocyclic bases, sugars and phosphate groups) in the interaction and to define optimal conditions for subsequent application to the fractionation of oligo- and polynucleotides.

Amino terminal sequence of the major component of human lymphoblastoid interferon

Homogeneous human lymphoblastoid interferon with an apparent molecular size of 18,500 daltons was characterized by its amino acid composition. Analysis of the amino terminal sequence by Edman degradation indicates that the sequence is unique.

Purification of mouse interferon by sequential chromatography

Two schemes for the purification of mouse interferon are described, based on the concerted application of various physicochemical and affinity/adsorption column chromatographic techniques. Mouse interferon was purified to a final specific activity of 1.0--8.0 x 10(8) units/mg when first precipitated with ammonium sulphate and further processed by hydrophobic chromatography and adsorption chromatography on AFFI-Gel 202 and Controlled Pore Glass. It was purified to a final specific activity of 2.5--3.7 x 10(8) units/mg when first precipitated with ammonium sulphate and further processed by gel filtration with Ultrogel AcA 54, ion-exchange chromatography with Carboxymethyl Boi-Gel Agarose, hydrophobic chromatography with AFFI-Gel 202 and adsorption chromatography with Controlled Pore Glass.