依赖雄激素的大鼠储精囊分泌蛋白的离子交换层析纯化

本文报道利用阳离子交换层析,纯化了雄激素依赖的大鼠储精囊分泌蛋白(SVPⅡ、SVPⅣ、SVPⅤ_a、SVPⅤ_b及SVPⅥ)。主要纯化步骤包括下列二步:1.Sep-hadex G-100凝胶过滤;2.上样后,联合使用盐梯度和pH梯度,洗脱快速蛋白液相层析(FPLC)系统的阳离子交换柱Mono S。洗脱峰的纯度以变性条件下的聚丙烯酰胶凝胶电泳(SDS-PAGE)和等电聚焦(IEF)鉴定;借此,还测定了已纯化的大鼠储精囊分泌蛋白的分子量和等电点。     

Interaction of chick oviduct progesterone receptor with immobilized aurintricarboxylic acid

Aurintricarboxylic acid (ATA) was immobilized on Sepharose 4B via a carbodiimide coupling mechanism. A majority of the chick oviduct progesterone receptor was retained on the affinity resin and could be recovered upon washing the column with buffer containing free ligand or 3 M guanidine-HCl. The [3H]progesterone-receptor complex retained its integrity following the chromatography on ATA-Sepharose as judged by sedimentation analysis. The procedure allowed significant purification of progesterone receptor: SDS-polyacrylamide gel electrophoresis of the purified preparation revealed elimination of many peptide bands present in the cytosol prior to ATA-Sepharose chromatography. The technique thus has a clear potential in characterization and purification of progesterone receptor.     

Improved method for rapid purification of protein kinase from streptomycetes

Protein kinase from Streptomyces lincolnensis was purified nearly to homogeneity using a high performance liquid chromatography (HPLC) and a Pharmacia FPLC system. The procedure used employed column chromatography on DE-53, followed by FPLC affinity chromatography with serine- or threonine-Sepharose (prepared as described in this paper) and gel filtration using a Superose 12 or TSK G3000SW column. Starting with 3.5 g of mycelial proteins, ∼ 1 mg of pure enzyme was obtained. The procedure is simple and highly reproducible. The protein kinase thus obtained was nearly pure by silver staining after sodium dodecyl sulfate-polyacrylaminde gel electrophoresis. The purified protein kinase phosphorylated substrate proteins at the seryl residues.     

Immunological similarity between the chick oviduct progesterone receptor forms A and B

A large-scale purification of the progesterone receptor from laying hens is described which yields apparently homogeneous form A and form B receptor in denatured form. The purification procedure is based initially on differential DNA affinity chromatography of both form A and B receptors. Under the conditions of preparation and activation described, progesterone receptor form B binds to DNA-cellulose even in the presence of 100 mM salt. This binding cannot be observed after thermal activation. Receptors obtained at 5% purity using conventional chromatographic purification steps were covalently cross-linked with radioactive ligand by photoaffinity labeling and purified to homogeneity using preparative gel electrophoresis systems under denaturing conditions. This material has been successfully used to generate polyclonal antibodies in rabbits. Immunoblots demonstrated a high degree of cross-reaction between anti-A antibodies and progesterone receptor form B, as well as between anti-B antibodies and progesterone receptor form A, using homogeneous as well as 5% pure receptors as probes. Implications of the immunological data and the novel DNA-binding characteristics of form B are discussed with respect to topological conformation of the progesterone receptor and the structural similarity between forms A and B.     

Single-step method for purification of Shiga toxin-1 B subunit using receptor-mediated affinity chromatography by globotriaosylceramide-conjugated octyl sepharose CL-4B.

A new single-step purification method for Shiga toxin (Stx) was developed using receptor-mediated affinity chromatography, in which Gb3Cer (globotriaosylceramide) was conjugated to octyl Sepharose CL-4B as a carrier. This method achieves high yield and high purity in a small column on which Gb3Cer has been immobilized at high density. Using this affinity column, the Stx1 B subunit was purified with homogeneity by a one-step procedure from a crude extract of recombinant Stx1 B subunit-producing Escherichia coli. The purified Stx1 B subunit conserved a natural pentamer structure confirmed by gel filtration and sedimentation equilibrium analysis. Furthermore, the purified Stx1 B subunit was able to bind specifically to Gb3Cer expressed on Burkitt's lymphoma cells. This versatile purification method can be used to isolate various types of natural as well as recombinant Stx, facilitating fundamental studies of human diseases caused by this toxin.     

Expression and Purification of Human Membrane Progestin Receptor α (mPRα)

Membrane progestin receptors (mPRs) are responsible for mediating the rapid, nongenomic activity of progestins and belong to the G protein-coupled receptor (GPCR) family. mPRs are also considered as attractive proteins to draw a new medicinal approach. In this study, we optimized a procedure for the expression and purification of recombinant human mPRα protein (hmPRα) by a methylotropic yeast, Pichia pastoris, expression system. The protein expressed in crude membrane fractions exhibited a binding affinity of Kd = 3.8 nM and Bmax = 288.8 fmol/mg for progesterone. These results indicated that the hmPRα expressed in yeast was active. Solubilized hmPRα was purified through three column chromatography steps. A nickel-nitrilotriacetic acid (Ni-NTA) column was first used, and the mPRα proteins were then bound to cellulose resin with free amino groups (Cellufine Amino) and finally passed through an SP-Sepharose column. The optimization of expression and purification conditions resulted in a high yield of purified hmPRα (1.3–1.5 mg from 1 L culture). The purified hmPRα protein demonstrated progesterone binding (Kd = 5.2 nM and Bmax = 111.6 fmol/mg). The results indicated that we succeeded in solubilizing and purifying hmPRα in an active form. Sufficient amount of active hmPRα protein will support the establishment of applications for the screening of ligands for mPRα.     

Purification and characterization of amine oxidase from pea seedlings

A novel, simple, and rapid procedure for the purification of pea seedling amine oxidase is reported. The crude enzyme, obtained by ammonium sulfate fractionation, was purified in two steps: the first one by anion-exchange chromatography and the second one by affinity chromatography. The first chromatography step was carried out on a diethylaminoethyl-cellulose column. By lowering the amount of protein loaded on the column and the buffer concentration it was possible to obtain an enzyme pure at 95% (sp act 1.2 microkat/mg). To achieve a higher degree of purification various affinity resins were prepared and tested. The resins were obtained by covalent immobilization of polyamines on Sepharose according to three different procedures. The best results were obtained with 6-aminohexyl-Sepharose 2B, prepared using CNBr as coupling agent, and eluting the enzyme by a solution containing 1, 4-diaminocyclohexane. This last compound was found to be a relatively strong competitive inhibitor of the oxidative deamination of cadaverine catalyzed by pea seedling amine oxidase (Ki = 32 microM). According to this procedure an electrophoretically homogeneous enzyme, characterized by a specific activity of 1.63 microkat/mg, was obtained.     

Purification and properties of chicken egg-white cobalamin-binding protein

A cobalamin-binding protein has been purified from chicken egg-white by using a combination of conventional and high performance ion-exchange chromatography. Following initial purification by DEAE-cellulose, ammonium sulphate precipitation, Sephacryl S-200 CM-cellulose and affinity chromatography, appropriate fractions were further purified using the Pharmacia fast protein liquid chromatography (FPLC) system. Using this method of purification, egg-white CBP has been purified more rapidly and with greater recovery than with conventional column chromatography. The homogeneity of this protein was verified by SDS-PAGE. The Mr was 37,000 by SDS-PAGE and 39,000 by gel filtration, which indicated that it was a glycoprotein. The stokes radius was 4.1 nm and pI was 4.3. The protein bound 57COB12 with a molar ratio of 1/1 and kd of 0.40 microM. The egg-white CBP was composed of 294 amino acid residues. Thiol groups and metal ions were not connected with the Cbl-binding activities.     

Involvement of a non-hormone-binding 90-kilodalton protein in the nontransformed 8S form of the rabbit uterus progesterone receptor

Nontransformed 8S progesterone receptor (8S-PR) was purified by hormone-specific affinity chromatography from rabbit uterine low-salt cytosol containing 20 mM molybdate. In the eluate obtained with radioactive progestin, sodium dodecyl sulfate-polyacrylamide electrophoresis (SDS-PAGE) showed the presence of several bands, including three that corresponded to approximately 90-, approximately 120-, and approximately 85-kDa proteins. None of these three proteins was found in the eluate of the affinity column when the molybdate-containing cytosol was chromatographed in the presence of nonradioactive progesterone ("mock purification"). Subsequent purification of the affinity eluate by DEAE-Sephacel chromatography gave a single radioactive receptor peak at 0.15 M KCl (approximately 20% yield, 19% purity on the basis of one binding site per approximately 100 kDa) with a sedimentation coefficient of 8.5 S. Silver staining after SDS-PAGE revealed that this purified 8S-PR fraction contained mainly the 120-, 90-, and 85-kDa proteins. [3H]R5020-labeled 8S-PR purified by DEAE-Sephacel column chromatography was UV irradiated, and after SDS-PAGE the 120- and 85-kDa proteins were revealed, but the 90-kDa protein was not.(ABSTRACT TRUNCATED AT 250 WORDS)     

Rapid purification yielding highly active 17β-hydroxysteroid dehydrogenase: application of hydrophobic interaction and affinity fast protein liquid chromatography

Homogeneous human placental 17β-hydroxysteroid dehydrogenase was obtained by a procedure consisting of two fast protein liquid chromatographic (FPLC) steps using Phenyl-Sepharose hydrophobic interaction and Blue-Sepharose affinity columns. In the first chromatography, the enzyme eluted only when an additional decrease in ionic strength was inserted after the ammonium sulphate concentration had reached zero, thus enhancing the separation. In the affinity chromatography, separation of contaminating proteins occurred at different stages of loading and washing. The specific elution of the enzyme by the co-factor NADP⁺ is very efficient in obtaining a homogeneous preparation in high yield. The rapidity of FPLC was further increased by a maximum simplification of the intermediate steps, and the whole procedure lasted only two days. This preparation has a yield of more than 50% and a high specific activity, catalysing the formation of 7.9 μmol of estrone from estradiol per minute at pH 9.2 and 23°C. It has an apparent molecular mass of 35 000. This provides an efficient candidate for the purification of other membrane-associated proteins.     

Estrogen sulfotransferase of mouse placenta: behaviour and characteristics during partial purification

Mouse placental estrogen sulfotransferase (ST) was partially purified by fast protein liquid chromatography (FPLC) gel filtration in combination with FPLC anion exchange. Owing to the highly unstable nature of the enzyme, large increases in specific activity were not obtained. Storage of the ST in the presence of thiol groups at -20 degrees C stabilized the enzyme considerably. Forty-three percent of the cytosolic ST was bound to an Affi-Gel blue column and eluted as a broad peak at approximately 0.8 M NaCl. The use of the latter procedure, in combination with FPLC gel filtration, did not increase the specific activity substantially. Larger increases in specific activity were obtained using agarose-hexane-adenosine-3',5'-diphosphate affinity chromatography. The bound ST activity was eluted under a single peak at 1 mM ADP. Increases in specific activity following use of this column averaged 54-fold but could reach 90-fold. Attempts at further purification of this material resulted in low recovery and decreased specific activity. Velocity versus substrate concentration curves show that estrone and particularly estradiol inhibit the partially purified mouse placental sulfotransferase above 0.1-0.25 microM substrate concentrations.     

Purification of the hepatic vasopressin receptor using a novel affinity column

A vasopressin receptor was purified, using a novel affinity column, from rat liver plasma membranes treated with guanosine 5'-(3-O-thio)triphosphate and solubilized with 0.8% cholate. Incubation of the membranes with the GTP analogue resulted in a dissociation of the receptor-guanine nucleotide regulatory protein complex. This manipulation, although resulting in a low-affinity state of the receptor, facilitated purification. The solubilized receptor was assayed using a new reconstitution procedure in which the soluble extracts were inserted into lipid vesicles composed of phosphatidylcholine and phosphatidylinositol. The receptor was purified by sequential chromatography on Q-Sepharose and hydroxyapatite. The use of a novel affinity column, a V1-vasopressin antagonist-agarose, resulted in a near-homogeneous preparation of a protein which exhibited an Mr = 58,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Autoradiography of purified receptor, as well as crude membrane preparations cross-linked to [125I]arginine vasopressin, also revealed a protein band with an approximate Mr = 58,000. These findings indicate that V1-antagonist affinity chromatography should be useful for purifying adequate amounts of the receptor for studies of structure and function.     

Purification of the intact monomeric 110 kDa form of the androgen receptor from calf uterus to near homogeneity

In the present study, calf uterine tissue has been used for isolation of androgen receptors. This tissue appeared to be a favourable source for large-scale purification of androgen receptors, because of the relatively high level of androgen receptors and the low concentration of proteolytic enzymes. The purification involved differential phosphocellulose and DNA affinity chromatography as first steps. The non-transformed receptor was passed through these matrices in order to remove contaminating DNA-binding proteins. After a transformation step to the DNA-binding state, the receptor was bound to DNA cellulose and subsequently eluted with MgCl2. A 0.5% pure androgen receptor preparation was obtained. Photoaffinity labelling with [3H]R1881 (methyltrienolone) was used to determine the size of the receptor at this stage of purification and during the following steps. Subsequently, isoelectric focussing of the partially purified androgen receptor preparation in an aqueous glycerol gradient was performed. In this step, the progesterone receptor, which is copurified with the androgen receptor protein during the first part of the purification procedure, focussed at pH 5.5 while the androgen receptor could be isolated at pH 5.8. The isoelectric focussing procedure could be applied in a preparative way for further purification of androgen receptors. After this step an approx. 8% pure preparation was obtained. Polyacrylamide gel electrophoresis of S-carboxymethylated androgen receptor was used as the final purification step. The [3H]methyltrienolone labelled androgen receptor from calf uterus was purified to homogeneity and consisted of one polypeptide with a molecular mass of 110 kDa.     

Simultaneous purification of DNA topoisomerase I and II from eukaryotic cells

We have developed a procedure for the simultaneous purification of DNA topoisomerase I and II from calf thymus. Both enzymes were first extracted from isolated nucleoprotein complexes. After batchwise chromatography on hydroxylapatite the two enzyme activities were separated on a FPLC phenylsuperose column. The enzymes were further purified by a second chromatography on phenylsepharose (topo I) or FPLC Mono Q (topo II). The purification can be finished within three days, yielding 0.5-1.0 mg quantities of homogeneous, enzymatic active preparations of the two proteins from 200 g of starting material.     

Estrogen receptor purification by affinity chromatography using an orange triazine dye

A rapid two-step procedure was devised for the purification of the estrogen receptor from the calf uterus. A 900- to 1700-fold purification of the estrogen receptor was obtained using ammonium sulfate precipitation followed by dye affinity chromatography with Reactive Orange 14 immobilized to Sepharose. The Reactive Orange 14-Sepharose was used to purify the estrogen receptor in the presence or absence of estradiol as well as to purify the progesterone receptor. The purified estrogen receptor retained its estradiol- and DNA-binding properties and sedimented into sucrose gradients as the 5 S receptor dimer. The Reactive Orange 14-Sepharose is easily prepared and offers a higher yield and purity of the estrogen receptor than that afforded by estrogen- or heparin-Sepharose chromatography.     

Brain casein kinase 2: affinity purification procedure using immobilized polyethylenimine.

A simplified procedure for casein kinase 2 purification from bovine brain is described. The purification procedure consists of two affinity chromatography steps, using heparin and polyethylenimine immobilized on a synthetic matrix (Toyopearl 650M). The adsorption and elution conditions for each column were optimized, resulting in a simple elution protocol for each column. A stable, highly purified casein kinase 2 preparation was obtained in 4 h using this procedure. Polyethylenimine was shown to stimulate the casein kinase 2 activity using exogeneous substrates (casein, calmodulin, MAP2, and tau) but not the enzyme's autophosphorylation activity. The polyethylenimine stimulation could be overcome by applying a mass excess of the casein kinase 2 inhibitor, heparin.     

Purification of the intact monomeric 110 kDa form of the androgen receptor from calf uterus to near homogeneity

In the present study, culf uterine tissue has been used for isolation of androgen receptors. This tissue appeared to be a favourable source for large-scale purification of androgen receptors, because of the relatively high level of androgen receptors and the low concentration of proteolytic enzymes. The purification involved differential phosphocellulose and DNA affinity chromatography as first steps. The non-transformed receptor was passed through these matrices in order to remove contaminating DNA-binding proteins. After a transformation step to the DNA-binding state, the receptor was bound to DNA cellulose and subsequently eluted with MgCl₂. A 0.5% pure androgen receptor preparation was obtained. Photoaffinity labelling with [³H]R1881 (methyltrienolone) was used to determine the size of the receptor at this stage of purification and during the following steps. Subsequently, isoelectric focussing of the partially purified androgen receptor preparation in an aqueous glycerol gradient was performed. In this step, the progesterone receptor, which is copurified with the androgen receptor protein during the first part of the purification procedure, focussed at pH 5.5, while the androgen receptor could be isolated at pH 5.8. The isoelectric focussing procedure could be applied in a preparative way for further purification of androgen receptors. After this step an approx. 8% pure preparation was obtained. Polyacrylamide gel electrophoresis of S-carboxymethylated androgen receptor was used as the final purification step. The [³H]methyltrienolone labelled androgen receptor from calf uterus was purified to homogeneity and consisted of one polypeptide with a molecular mass of 110 kDa.     

Electrophoretic characterization of purified bovine, porcine, murine, rat, and human uterine estrogen receptors

The calf uterine estrogen receptor (E2R) in the presence of sodium molybdate has been purified, 7,000-fold by a single passage over an estradiol affinity column. A dominant 70,000-dalton band and two minor bands at 50,000 and 30,000 daltons were observed by electrophoretic analysis. These bands had been eluted using estradiol, sodium sulfocyanate, CHAPS, and HEPES (pH 7.4) with insulin as a carrier protein. The identities of the protein bands were initially confirmed by their failure to bind the affinity column when saturated with estradiol. This single step purification procedure was reproducible and rapid, with yields of 10-20%, providing 25% purity. Diffusion blot analysis, with specific 35S- and 125I-labeled monoclonal antibodies to E2R, confirmed that the 70,000-dalton band represented the estrogen receptor. Specificity was demonstrated by inhibition of binding of purified E2R by both estradiol and diethylstilbestrol but not testosterone, progesterone, corticosterone, aldosterone, or hydrocortisone. The relative binding affinity of the purified receptor was: ethynyl estradiol greater than 17 beta estradiol greater than estriol greater than or equal to estrone greater than or equal to 17 alpha-estradiol greater than mestranol. Pig, human, mouse, and rat uterine estrogen receptors were similarly purified with the affinity column. As with the calf uterine preparations, a dominant 70,000-dalton band with minor bands at 50,000 and 30,000 daltons was identified by diffusion blot analysis in all the species examined.     

One-step affinity purification of Bacillus neutral proteases using bacitracin-silica

A purification procedure for neutral proteases from bacilli is described, in which bacitracin-silica was used as affinity medium. This enabled a one-step purification of the proteases directly from culture supernatant. Since neutral proteases are extremely sensitive towards autodigestion, conditions were chosen such, that autodigestion was largely prevented. Isopropanol appeared to be useful in both eluting the enzymes from the affinity medium, and inhibiting enzymatic activity during this step. The bacitracin-silica medium allowed high flow rates: with columns prepared for use in an FPLC system flow rates up to one column volume per minute were feasible, and still gave satisfactory results. The neutral proteases purified by this method were found to be homogeneous both by SDS-PAGE and analytical gel filtration.     

Purification of the c-fos enhancer-binding protein.

We have purified the c-fos enhancer-binding protein from HeLa cell nuclear extracts. The key purification steps involved chromatography on a nonspecific DNA affinity column, from which binding activity and other protein were eluted at low salt concentrations, followed by chromatography on a specific oligonucleotide affinity column, from which the enhancer binding activity was specifically eluted at high salt concentrations. The purified protein had a strong affinity for the c-fos enhancer dyad symmetry sequence, with an equilibrium dissociation constant of 3.3 x 10(-11) M. This affinity was at least 50,000-fold stronger than that found for nonspecific DNA sequences.