Spectrophotometric measurement of dodecyl sulfate with basic fuchsin

The role of a heat shock protein from V. cholerae 0139 in the gut immune response

An immunodominant heat shock protein (Hsp 24) was purified from Vibrio cholerae O139 at 42 degrees C and used as an immunomodulator for studying the gut immune response. T cell clone and T cell line specific for the Hsp 24 were generated from the lymphocytes of lamina propria and intra-epithelial lymphocytes of mice orally infected with V. cholerae O139, respectively. The T cell clone was TCR alphabeta(+), CD4(+) and appeared to play an important role in the functioning of gut B-lymphocytes. The T cell line had heterogenous population of CD8+ and CD4+ cells, most of which were found to be TCR alphabeta(+) and a minor population was TCR gammadelta(+). The lymphokine profile of T cell line showed IFN-gamma to be the most abundant lymphokine followed by IL-2 and IL-4. The possible involvement of alternative pathway of activation for T cell clone was also addressed in this study. The splenocytes showed an up-regulation of their CD2 receptor expression on stimulation with the Hsp-24. The pattern of lymphokines released by splenocytes stimulated with the Hsp-24 showed no particular cell type to be responsible for mounting immune response. Thus, there is involvement of both, mucosal and peripheral arm of the immune system.

Interaction of a low mobility group protein, LMG160, with deoxyribonucleic acid

A fraction of low mobility group (LMG) nonhistone protein designated LMG(160) was isolated from rat liver chromatin by preparative gel electrophoresis and its interaction with DNA was studied using thermal denaturation and DNA-cellulose affinity chromatography techniques. The results showed that LMG(160) with an isoelecteric point of 5-5.5 was bound to DNA and decreased its melting temperature. Increasing ionic strengths decreased this effect. DNA-cellulose affinity chromatography showed the affinity of LMG(160) to double stranded DNA was higher than that to single stranded DNA, since it required 0.6 M NaCl for elution. The results suggest that LMG(160) protein preferentially binds to double stranded DNA destabilizes it and the binding is electrostatic.

Coating of cationized protein on engineered nanoparticles results in enhanced immune responses

A significant emphasis has been placed on the development of improved adjuvants and delivery systems to improve both antibody production and cell-mediated immunity. The overall goal of this project was to cationize a model protein antigen, beta-galactosidase (nGal), coat the cationized Gal (cGal) on the surface of novel anionic nanoparticles engineered from microemulsion precursors, and assess the immune response of this system after subcutaneous injection to mice. Gal was chemically cationized as evidenced by gel electrophoresis. The cGal was coated on anionic nanoparticles (78+/-11 nm) engineered from oil-in-water microemulsion precursors to produce cGal-coated nanoparticles. The immune response to nGal with 'Alum', cGal alone, and cGal-coated nanoparticles were assessed after subcutaneous injection to Balb/c mice. cGal alone elicited similar antibody titer to nGal with 'Alum'. However, cGal-coated nanoparticles elicited the strongest and most reproducible antibody titer. cGal alone produced very high levels of Th1 cytokines, but low levels of Th2 cytokines. In contrast, cGal-coated nanoparticles significantly enhanced both the Th1 and Th2 cytokines. The results demonstrated the utility of antigen-coated nanoparticles to enhance both the humoral and Th1-type immune responses, in parallel.

Novel anionic microparticles are a potent adjuvant for the induction of cytotoxic T lymphocytes against recombinant p55 gag from HIV-1

Microparticles with entrapped antigens have recently been shown to possess significant potential as vaccine delivery systems and adjuvants. However, the potential of microparticles as adjuvants has been seriously limited by the common problem of degradation and denaturation of antigens following encapsulation and release. To overcome these problems, we have developed a novel way to use microparticles as adjuvants, by the adsorption of proteins onto their surface. Anionic microparticles were prepared through the inclusion of an anionic detergent, sodium dodecyl sulphate (SDS), in the microparticle preparation process. The anionic microparticles were capable of the efficient and reproducible adsorption of recombinant p55 gag protein from HIV-1. Microparticles with adsorbed p55 were capable of inducing potent cytotoxic T lymphocyte responses in mice following intramuscular immunization. In addition, the microparticles also exhibited a potent adjuvant effect for antibody induction against p55.

Complete removal and exchange of sodium dodecyl sulfate bound to soluble and membrane proteins and restoration of their activities, using ceramic hydroxyapatite chromatography

Up to now, removal of sodium dodecyl sulfate (SDS) from proteins in terms of restoration of their activity was an unsolved problem. A general procedure using ceramic hydroxyapatite (HAP) chromatography was developed for the complete removal of SDS bound to soluble or membrane proteins. This procedure involves (i) the binding of the SDS-protein complexes onto the ceramic hydroxyapatite column, (ii) extensive washing of bound proteins with phosphate buffer containing a mild detergent to exchange SDS, (iii) elution of the retained protein by increasing the phosphate concentration. Using this approach, complete exchange of [35S]SDS into a nonionic detergent such as dodecyl maltoside was achieved with a 90-100% protein recovery. The efficiency of protein-bound SDS removal is very likely due to the combined effect of phosphate ions and the hydrophobic tail of nonionic detergent: acting together, they are able to displace SDS molecules from their protein-binding sites. The advantages of this HAP-mediated SDS removal method include high efficiency, rapidity, simplicity and general applicability to a wide variety of detergents and soluble or membrane proteins. Of utmost importance, SDS-treated P-glycoprotein, glutamate dehydrogenase, and lysozyme fully recovered their enzymatic activities after HAP chromatography, including lysozyme electroeluted from SDS-polyacrylamide gel electrophoresis. This demonstrates that reactivation of SDS-treated protein can be achieved, provided that SDS is completely removed under mild conditions.

Novel 29 kDa heparin-binding lectin from human foetal brain

Heparin inhibitable lectins are physiologically important because of their interactions with extracellular matrix and with other cell surface glycoconjugates. However, due to the unstable nature of these animal lectins, it becomes necessary to purify them in the shortest possible time. In the present study, a chromatographic procedure was developed to separate heparin inhibitable lectin activity. Lectin activities from human foetal brain were separated on a Q-Sepharose column employing different equilibration conditions. When proteins were loaded on to a phosphate-buffered saline (PBS) equilibrated column and eluted with salt gradient, only one lectin peak was obtained. However, when proteins were loaded on to a hypotonic equilibrated column and eluted with a salt gradient, four lectin peaks were obtained. The lectin peak obtained from the PBS equilibrated column was characterized as heparin inhibitable lectin. On SDS-PAGE analysis, it gave a single band of 29 kDa. For optimum lectin activity, a pH of around 7.0 was required. Lectin activity was stimulated by Mn++; amino acid composition was different from other known lectins. The lectin was particularly rich in acidic amino acids. Regional distribution of 29 kDa lectin in different foetal brain regions gave the highest content in the cerebral cortex, showing a caudoroastral distribution. Determination of the subcellular distribution of the lectin in the foetal cerebral cortex gave the highest value with a mitochondrial fraction.

Characterization of a novel co-stimulatory molecule: a 155-160kD B cell surface protein provides accessory help to CD4+ T cells to proliferate and differentiate

Optimal activation of T cells to clonally expand requires at least two distinct biological signals; one is generated by the interaction of the T cell receptor (TcR) with peptides bound to MHC molecules. The other signal(s) is (are) generated by a functionally defined event called the co-stimulatory pathway. We have characterized the co-stimulatory property of a murine B lymphocyte membrane protein (155-160 kD) on resting CD4+ T cells. The study involved the isolation of a 155-160 kD protein (B1) from the membranes of LPS-stimulated B cells. When reconstituted into lipid vesicles, B1 exerted a dose-dependent proliferative response to CD4+ T cells, resulting in the predominant secretion of IL-4 and IL-5 after cross-linking receptors with anti-CD3 mAb. This protein is a phosphoglycoprotein which gives a single spot on two-dimensional gel electrophoresis under reducing conditions and as a distinct peak on reverse phase-HPLC. The B1 binds to the T cell surface as is demonstrated by electron microscopic autoradiography and scanning electron microscopy, as well as competitive binding assays. It does not cross-react with antibodies directed against ICAM-1, LFA-1 alpha, B7, HSA and VCAM-1, suggesting the novelty of the protein. Activation of CD4+ T cells with B1 in the presence of anti-CD3 resulted in the translocation of protein kinase C (PKC). The B1 is barely detectable on the surface of resting B cells and digestion of this protein with V8 protease and peptide N-glycosidase F resulted in distinct protein bands on an autoradiogram.

Preparative scale purification of recombinant proteins to clinical grade by isotachophoresis

An electrophoretic procedure based on isotachophoresis has been developed for protein purification on a preparative scale in the 10 to 500 mg range. The system is simple, uses well understood physical properties, does not need ampholyte spacers and is able to produce sterile products of clinical grade. We demonstrate the applicability of this apparatus for the purification of denatured recombinant proteins and complex mixtures of proteins. The system may also be used for both cationic and anionic purification of proteins in their native form. The system is scalable from analytical to preparative protein loads at consistently high protein yields and purity levels. Total protein loads may vary as much as 1000 fold with the use of interchangeable columns of varying diameter and constant length. At both preparative and analytical scales concentration of products at greater than 20 mg/ml are obtainable. Toxicological considerations are addressed with assays for endotoxin, acrylamide and SDS concentrations, as well as the prevention of covalent protein modification.

Characterization of novel costimulatory molecules. A protein of 38-42 kDa from B cell surface is concerned with T cell activation and differentiation

Optimal activation of T cells often requires signals delivered by the ligation of T cell receptor (TcR) and those resulting from costimulatory interaction between certain T cell surface accessory molecules and their respective counter receptors on antigen presenting cells. The molecular events underlying the co-stimulatory activity are still not understood fully. Here we describe a 38-42-kDa (B3) protein, present on the surface of lipopolysaccharide-activated B cells, which can provide co-stimulation to resting T cells leading to a predominant release of interleukin (IL)-4 and IL-5 and negligible amounts of IL-2 and interferon-gamma. Binding assay and electron microscopic autoradiography data suggest that this molecule binds T cells, and the same can be competed by unlabeled B3. Characterization experiments point out that B3 shows up as a single prominent peak on reverse phase-high performance liquid chromatography, runs as a single spot in reducing two-dimensional gel electrophoresis, and is a phosphoglycoprotein. The Western analysis indicate that it does not cross-react with antibodies directed against murine ICAM-1, LFA-1 alpha, VCAM-1, HSA, and B7 suggesting the novelty of the protein. The internal amino acid sequence of this molecule suggests that it does not belong to a known category of murine B cell surface molecules.

Involvement of N-linked carbohydrate chains of pig zona pellucida in sperm-egg binding

The sperm receptor activity of pig zona pellucida has been previously shown to exist in one of the components, pig zona protein 3 alpha (PZP3 alpha), that can be purified after the removal of sialylated and/or sulfated N-acetylpoly(lactosamine) by digestion with endo-beta-galactosidase. In this study, we examined whether N-linked or O-linked carbohydrate chains are involved in the sperm receptor activity of pig zona pellucida. The elimination of N-linked carbohydrate chains from endo-beta-galactosidase-digested PZP3 alpha by digestion with N-glycanase markedly reduced its inhibitory effect on sperm-egg binding in an in vitro competition assay, whereas the elimination of O-linked carbohydrate chains by alkali treatment hardly reduced the inhibitory effect. These results indicate that N-linked carbohydrate chains of PZP3 alpha play a major role in mediating the sperm binding of zona pellucida in pig.

Characterization of a serum factor that decreases albumin mRNA in cultured hepatocytes

When primary cultures of hepatocytes are exposed to media containing fetal bovine serum (FBS) there is a rapid decrease in levels of tissue-specific mRNAs such as albumin mRNA. We used Northern blot analysis to examine mRNA levels in cultured hepatocytes, and characterized the factor in FBS that significantly reduces the steady state albumin mRNA level. Neonatal bovine serum or serum derived from platelet-poor calf plasma proved as potent as did FBS, but commercial bovine serum albumin did not exhibit this inhibitory activity. Inhibitory activity of FBS was not removed by moderate heat treatment, dialysis, or extraction with organic solvents. However, incubation of FBS with a highly anionic detergent such as 0.1% sodium dodecyl sulfate or N-lauroyl sarcosine, followed by extensive dialysis, resulted in sera that did not inhibit expression of albumin mRNA. These sera supported cell attachment and seemed non-toxic toward the cells. Ammonium sulfate fractionation of FBS showed the activity was present in the 45 to 70% fraction, and trypsin digestion destroyed the inhibitory activity. Gel exclusion chromatography gave a molecular weight of 60,000 to 70,000. Fractionation of serum proteins by DEAE-Sephacel or Cibacron blue-agarose showed enrichment for albumin in the most active fractions. Interestingly, metabolic labeling of secreted and cellular proteins with 35S-methionine and cysteine showed no significant difference between hepatocytes maintained for 2 days beforehand in serum-free or serum-supplemented media, and no difference between detergent-treated FBS and control FBS.(ABSTRACT TRUNCATED AT 250 WORDS)

Localization of the colchicine-binding site of tubulin

We have previously shown that rat brain tubulin, a heterodimer consisting of an alpha and beta monomer, can be covalently labeled with [3H]colchicine by near UV irradiation. Most of the label appears in beta-tubulin. We show here that beta-tubulin can be separated and purified from SDS preparative gels and analyzed by proteolysis. Chymotrypsin yielded a labeled approximately 4-kDa band that contained two peptides. Tryptic digestion also yielded an approximately 4-kDa band containing two peptides. Sequence analysis revealed a peptide of residues 1-36 and 213-242 for chymotrypsin and a peptide of residues 1-46 and 214-241 for trypsin. To identify which peptide carried the label, limited hydrolysis of beta-tubulin was done with trypsin; this procedure yielded a labeled 16-kDa N-terminal peptide and a 35-kDa C-terminal peptide, as identified by antibodies. Isolation of these peptides and extensive digestion with trypsin yielded two labeled peptides corresponding to residues 1-46 from the 16-kDa N-terminal fragment and residues 214-241 from the 35-kDa C-terminal fragment. These results show that at least two regions in beta-tubulin are specifically involved in colchicine binding and that the span of the colchicine molecule, < or = 11 A, bridges these two regions in the native beta monomer.

Separation of proteins by consecutive sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and reversed phase high performance liquid chromatography

A procedure for the preparative separation of proteins was developed by using consecutively sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (SDS-PAGE) and reversed phase high performance liquid chromatography (HPLC). The proteins were separated by SDS-PAGE and afterwards extracted from the gel. The extracted proteins were separated from SDS and other small molecular weight contaminants on a Fractogel TSK HW-40 (F) column in acidic aqueous acetonitrile. The proteins eluted from the Fractogel column were fractionated by HPLC. The identity and purity of the recovered proteins was confirmed by SDS-PAGE analysis.

Strategies for internal amino acid sequence analysis of proteins separated by polyacrylamide gel electrophoresis

An evaluation has been made of various strategies for obtaining internal amino acid sequence data from electrophoretically separated proteins. Electroblotting, in situ proteolysis and extraction, and direct electroelution are compared. Electroblotting of protein or peptides from gels resulted in poor yields (typically, 1-7%). However, higher yields (3-67%) were achieved by in situ enzymatic cleavage followed by acid extraction of the peptides from the gel. Peptides extracted from the gel were separated by reversed-phase high-performance liquid chromatography (RP-HPLC), on short, small-bore columns (100 x 2.1 mm I.D.), to enable recovery of peptides in small volumes (ca. 50 microliters) suitable for microsequence analysis. Capillary zone electrophoresis under acidic conditions (pH 2.5) was used to assess peptide purity before sequence analysis. Cysteine residues were identified in unmodified proteins or peptides by a characteristic phenylthiohydantoin (PTH)-amino acid derivative during sequence analysis. This derivative does not co-chromatograph with any known PTH-amino acid. Direct electrophoretic elution of protein from gels yielded between 45-50% of applied protein. Proteins recovered from gels by electrophoretic elution required further purification by inverse-gradient RP-HPLC [R. J. Simpson, R. L. Moritz, E. C. Nice and B. Grego, Eur. J. Biochem., 165 (1987) 21] to remove sodium dodecylsulphate and acrylamide-related contaminants for sequence analysis.

Removal of sodium dodecyl sulphate from proteins isolated by sodium dodecyl sulphate polyacrylamide gel electrophoresis

A procedure is described for the removal of sodium dodecyl sulphate (SDS) from proteins isolated by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). The proteins separated by SDS-PAGE were stained with Coomassie Blue and extracted with Tris-HCl buffer containing SDS. The obtained extracts were subjected to gel permeation chromatography in an acidic aqueous acetonitrile solution. The procedure allows purification of the isolated proteins not only from SDS, but also from Coomassie Blue, buffer salts and other small molecular weight contaminants.

Differential refractometric determination of binding of sodium dodecyl sulfate to protein using high-performance gel chromatography

When sodium dodecyl sulfate (SDS) is added to a high-performance gel chromatographic column equilibrated with a buffer solution containing SDS at a level above the critical micelle concentration, the surplus SDS migrates as micelles giving a sharp peak. The presence of an unfolded protein in the sample solution gives a polypeptide peak in advance of the SDS micelle peak. As the result of SDS binding to the polypeptide, the SDS micelle peak is attenuated in comparison to that in the absence of protein. Thus the amount of SDS bound to the polypeptide can be determined accurately and simply from the decrease in the area of the SDS micelle peak. This approach is particularly useful for precise determination of bound SDS, which is pertinent to understanding the state of the protein polypeptide-SDS complex under the conditions of SDS-polyacrylamide gel electrophoresis.

A high-performance liquid chromatography procedure for recovering subnanomole amounts of protein from SDS-gel electroeluates for gas-phase sequence analysis

A high-performance liquid chromatographic procedure for recovering subnanomole amounts of protein from SDS/polyacrylamide gel electroeluates in a form suitable for gas-phase sequence analysis has been developed. By a judicious choice of reversed-phase column packing, proteins can be retained at high concentrations of n-propanol (90-100%) where sodium dodecylsulfate and acrylamide gel-related contaminants are washed through the column. Retained proteins can be recovered from the column in high yield (greater than 90%) by the simultaneous adding of an ion-pairing reagent into the mobile phase and elution with a gradient of decreasing n-propanol concentration (i.e. an 'inverse or negative gradient'). Furthermore, by using a steep gradient (e.g. 50%/min) at a low flow rate (20-200 microliters/min) the proteins can be recovered in less than 100 microliters and can be used for gas-phase sequence analysis without further manipulation. This procedure is independent of sodium dodecylsulfate concentration (up to 1.2% w/v) in sample loading volumes of up to 1.5 ml. Microbore columns (2.1 mm internal diameter) have been employed for recovering small amounts of protein (1-100 micrograms from electroeluates of protein-containing gel spots while conventional columns (4.6 mm internal diameter) were used for isolating larger amounts of protein (greater than 500 micrograms) from electroeluates of preparative gel bands. The general utility of this inverse-gradient high-performance liquid chromatography procedure has been demonstrated by its successful application in recovering a wide variety of proteins from sodium dodecylsulfate gel electroeluates in a form suitable for N-terminal sequence analysis in the 10-500 pmol range.

Preparative fractionation of amyloid proteins on a microgram scale by high-performance liquid chromatography and polyacrylamide gel electrophoresis

Preparative separation of amyloid proteins on a microgram scale is presented. Amyloid fibrils solubilized in aqueous 50% acetonitrile containing 0.1% trifluoroacetic acid, are fractionated by reverse-phase high-performance liquid chromatography. Fractionation of amyloids obtained from patients with familial Mediterranean fever allowed isolation of a protein identical with a conventionally isolated AA-protein. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis is used for preparative separation of AL-proteins. Two protein extraction procedures from Coomassie Blue stained gels are applied using elution in 0.1% sodium dodecyl sulfate containing buffer and 6 mol/l guanidine-HCl solution. The eluted proteins are concentrated and sodium dodecyl sulfate and dye are removed by acetonitrile precipitation of sample.

Purification and properties of rubrophilin: a novel brain specific membrane polypeptide

Rubrophilin, a unique brain specific polypeptide, was purified to apparent homogeneity from microsomal fractions of bovine brains. The peptide stains pink with Coomassie Brilliant Blue R-250 (C.I. No. 42660) under specific conditions, has an apparent Mr of 53,000, and is acidic with an apparent pI of 4.9. The purification involves initial solubilization of delipidated microsomes in sodium dodecyl sulfate, followed by ammonium sulfate fractionation, reversed ammonium sulfate gradient elution from diatomaceous earth, gel filtration on polyacrylamide (Biogel P-200), gradient elution chromatography from hydroxylapatite, and reverse-phase chromatography from phenyl-Sepharose. A yield of about 5 mg of rubrophilin was obtained from 9 g of microsomal proteins. Amino acid analysis shows that rubrophilin contains only nine amino acids with residues/mol as follows: alanine (102), glutamic acid (97), lysine (65), proline (55), aspartic acid (48), glycine (44), serine (37), threonine (35), and valine (10). Cysteine, methionine, tryptophan, tyrosine, isoleucine, phenylalanine, histidine, and arginine could not be detected. Relative rubrophilin content of vertebrate brains was as follows: mammals greater than birds greater than reptiles greater than fishes. It is present in mouse retina and human neuroblastoma cell cultures but could not be detected in octopus optic lobe or in cultured C-6 rat glioma cells.

Isolation and immunological characterization of the four non-identical subunits of the soluble NAD-linked hydrogenase from Alcaligenes eutrophus H16

The soluble NAD-linked hydrogenase of Alcaligenes eutrophus H16 is a tetramer consisting of 4 non-identical subunits with molecular weights of 63,000, 56,000, 30,000 and 26,000. Conditions have been elaborated to separate and isolate each of these subunits as a single polypeptide by a preparative scale of polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate (SDS). Against each of the 4 subunits, polyclonal antibodies were produced. From the crude sera isolated from rabbits, the antibodies (IgG fractions) were purified by Protein A-Sepharose chromatography. By the double immunodiffusion method, comparison of the 4 types of subunits revealed that they are in fact different polypeptides. Subunit 1 (Mr = 63,000) and subunit 2 (Mr = 56,000) only reacted with their own specific antibodies and showed no cross-reaction whatsoever with the antibodies raised against the other subunits. The only immunological relationship among the different subunits was observed with subunit 3 (Mr = 30,000) and subunit 4 (Mr = 26,000); the type of cross-reaction indicated that they are partially identical. A. eutrophus H16 contains, in addition to the soluble hydrogenase, a membrane-bound hydrogenase which is a dimer composed of 2 subunits with Mr of 61,000 and 30,000. Whereas the 2 native enzymes did not show any immunological cross-reaction with the respective antibodies, it was demonstrated by double immunofluorescence labeling on nitrocellulose filters that the larger subunit of the membrane-bound hydrogenase cross-reacted significantly with the antibodies raised against subunit 2 of the soluble hydrogenase.(ABSTRACT TRUNCATED AT 250 WORDS)

Functional characterization of human erythrocyte spectrin alpha and beta chains: association with actin and erythrocyte protein 4.1

Human erythrocyte spectrin alpha and beta chains were purified by preparative sodium dodecyl sulfate gel electrophoresis and also by DEAE-cellulose chromatography in the presence of urea. The purified chains behaved as individual monomers on sucrose gradients and did not form homodimers. Recombination of the chains led to the formation of alpha-beta heterodimers with sedimentation characteristics identical with native alpha-beta dimers. The binding of 125I-labeled band 4.1 to alpha and beta chains was measured by sucrose gradient rate zonal sedimentation and by quantitative immunoassay. It was found that both alpha and beta chains associated with 125I-labeled band 4.1 in a nearly identical manner over the range of band 4.1 concentration studied. The association was abolished by heat denaturation of the spectrin chains or by denaturation of band 4.1 with a 40-fold molar excess of N-ethylmaleimide. As expected, purified beta chains but not alpha chains bound to 125I-labeled ankyrin as measured by a quantitative radioimmunoassay. The binding of purified alpha chains, beta chains, and recombinant alpha-beta heterodimers to F-actin was measured in the presence of band 4.1. We found that alpha or beta chains separately exhibited no band 4.1 dependent association with F-actin but that alpha-beta heterodimers formed by recombination of the chains did. We conclude that spectrin binding to F-actin in the presence of band 4.1 requires the participation of both of spectrin's polypeptide chains.

Similarities between stratum corneum basic protein and histidine-rich protein II from newborn rat epidermis

The stratum corneum basic protein and histidine-rich protein II were each isolated from newborn rat epidermis and compared by biochemical and immunologic methods. The proteins were indistinguishable by immunodiffusion using antiserum elicited to either protein. The migration of the proteins on SDS-polyacrylamide gel electrophoresis was identical giving a molecular weight of 49 000. These proteins, which have similar but unusual amino acid compositions, give very similar tryptic peptide maps. Both proteins aggregate with keratin filaments to form macrofibrils. These results suggest that histidine-rich protein II and stratum corneum basic protein are the same protein. We suggest that this protein be called histidine-rich basic protein.

Removal of sodium dodecyl sulfate from proteins

Effective removal of sodium dodecyl sulfate from proteins in water or sodium phosphate buffer was achieved by column chromatography using the ion-retardation resin AG11A8. An average recovery of 83% protein was obtained, while 0.1 to 1.4 moles of sodium dodecyl sulfate remained on each mole of protein.

A simple procedure for obtaining large quantities of tubulin subunits from newborn mouse brain

A simple, efficient two-step procedure of DEAE--Sephadex A--50 column chromatography followed by hydroxyapatite column chromatography for purification of alpha- and beta-tubulin subunits from newborn mouse brain is described. Stored frozen mouse brains can be used as a convenient starting material. Differential elution of alpha and beta subunits from hydroxyapatite was achieved using a linear gradient of 0.2--0.3 M phosphate buffer containing 2 M urea, 0.1% sodium dodecyl sulphate and 1 mM dithiothreitol. 20 mg of alpha-tubulin (purity: greater than 85%) and 16 mg of beta-tubulin (purity greater than 95%) completely separated from each other can be obtained in one experiment.