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PubMed1990

Separation processes in biotechnology. Ion-exchange processes.

Through the use of several differentiating mechanisms, ion exchangers can separate ionic and nonionic materials, solutions containing only ionic species, and even completely nonionic mixtures. Although the mechanisms are distinct in their mode of operation, the resin characteristics that influence the results are largely the same. A practical understanding of the resin properties involved is all that is necessary to begin to use ion-exchange resins successfully. Ion exchange owes most of its history to water treatment, which has provided the economic and technological driving force in the past for the development of improved resins. However, specialty applications such as those in biotechnology are steadily becoming major factors in industry, perhaps not in shear volumes of resin used, but certainly in the value added by the process. The field of biotechnology no doubt holds many of the exciting new applications for ion exchange.

Adsorption↗

PubMed1976

Oxalic acid determination in plasma.

A method is described for the estimation of oxalic acid in plasma. After removing interfering substances with an ion-exchange resin, oxalic acid is reduced to glycolic acid, which forms a coloured compound with chromotropic acid. No special equipment is required. A good recovery and precision are found.

Chromatography, Ion Exchange↗

PubMed1997

Simple high-performance liquid chromatographic method for the detection of phenylpropionylglycine in urine as a diagnostic tool in inherited medium-chain acyl-coenzyme A dehydrogenase deficiency.

Deficiency of medium-chain acyl-CoA dehydrogenase is a frequent and treatable metabolic defect, which can be diagnosed by detection of phenylpropionylglycine in urine after an oral load of phenylpropionic acid. We studied the determination of phenylpropionylglycine in urine by isocratic ion-exclusion chromatography on a cation-exchange column using water-sulphuric acid (pH values between 2 and 4) as mobile phase. Phenylpropionylglycine, phenylpropionic acid and hippuric acid exhibited high retention factors with only a slight decline at increasing solvent pH. This resulted in a good separation from interfering substances after direct injection of urine. We hypothesize that pi-pi interactions between the aromatic carbonic acids and the ion-exchange resin are responsible for the strong retention on the stationary phase. We conclude that, even in asymptomatic patients, determination of phenylpropionylglycine in urine after a phenylpropionic acid load by ion-exclusion chromatography is a rapid and reliable diagnostic tool for the detection of medium-chain acyl-CoA dehydrogenase deficiency.

Acyl-CoA Dehydrogenase↗

PubMed1997

X-ray fluorescence used to characterize the salt content of proteins.

The quantitative measurement of the salt content in solid protein samples was performed using X-ray fluorescence. Linear calibration curves were obtained for chloride, calcium and sulfur using sulfur and chloride as internal standards in the range 1-10 protein molar equivalents. The detection limit was approximately 0.02 molar equivalents for chloride and less than 0.01 molar equivalents for calcium. X-ray fluorescence thus provides a non-destructive sensitive method of testing the efficiency of different purification methods. Commercial hen egg white lysozyme samples contain from 15 to 46 molar equivalents of chloride, whereas the calcium content remains less than 0.2 equivalents. Deionization on ion-exchange resins is a very efficient tool for removing ionic species since deionized lysozyme samples contain less than 0.34 molar equivalents of chloride. Extensive dialysis against water only partially removes chloride ions, the residual chloride content corresponding to the number of counter-ions necessary to ensure the electroneutrality of lysozyme when dissolved in water.

Journal Article↗

PubMed1986

Cooperative cluster formation in metallothionein.

An ion-exchange chromatography procedure was used to resolve apometallothionein from the metallo- form in a study of metal-thiolate cluster formation. Chromatography of metallothionein reconstituted with Cd(II), Zn(II), or Cu(I) at neutral pH on carboxymethyl-cellulose led to removal of apoprotein from a solution without effect on recovery of the metalloprotein. Analysis of the effluent revealed apparent cooperative binding of these metal ions to the protein. Addition of 1-4 mol eq Cd(II) ions led to the recovery of metallothionein with around 4 mol eq Cd bound. The yield of this form increased with increasing starting metal ion equivalency. These results were obtained with two different ion-exchange resins. The cooperativity of binding was not total, but was initially confined to the carboxyl-terminal alpha domain. The results of metal and protein yields are inconsistent with random, noninteractive binding. Similar data were obtained with Zn(II) and Cu(I) ions although Cu(I) exhibited initial cooperative binding within the amino-terminal beta domain with over 5 mol eq Cu(I) bound.

Allosteric Site↗

PubMed1975

On the properties of solid and liquid ion exchangers. II. Infrared and NMR studies of lithium and cesium salts of dinonylnaphtalene sulfonic acid in heptane.

Infrared and NMR measurements on solutions of lithium and cesium dinonylnaphtalene sulfonates (DNNS-salts) in heptane show that the state of water in these systems is in several respects similar to its state in solid ion exchange resins and in some respects also similar to that in ordinary water. The two cations differ in their interaction with the sulfonic acid group at low water contents, the interaction being stronger for Li+. Spin-lattice relaxation measurements on LiDNNS show that the state of lithium both in DNNS and in solid resins is quite different from that of lithium salts in aqueous solutions of the corresponding concentration.

Chromatography, High Pressure Liquid↗

PubMed1981

A simple radioenzymatic method to measure picogram amounts of DOPA in brain and biological fluids.

A simple radioenzymatic method for the determination of DOPA is described. The method is based on the conversion of DOPA to 3-O-[methyl-3H]DOPA by catechol-O-methyltransferase in the presence of S-adenosyl-[methyl-3H]methionine and purification of the labelled product by Sephadex G10 and Dowex 50 W x 4 ion exchange resin. The method has been applied to the assay of endogenous DOPA in different brain area and to measuring DOPA accumulation after inhibition of aromatic amino acid DOPA decarboxylase.

Animals↗

PubMed2006

Purification by expanded bed adsorption and characterization of an alpha-amylases FORILASE NTL from A. niger.

In this work the purification and biochemistry characterization of alpha-amylases from Aspergillus niger (FORILASE NTL) were studied. The effects of expansion degree of resin bed on enzyme purification by expanded bed adsorption (EBA) have also been studied. Residence time distributions (RTD) studies were done to achieve the optimal conditions of the amylases recovery on ion-exchange resin, and glucose solution was used as a new tracer. Results showed that height equivalent of the theoretical plates (HETP), axial dispersion and the Prandt number increased with bed height, bed voidage and linear velocity. The adsorption capacity of alpha-amylases, on the resin, increased with bed height and the best condition was at four-expansion degree. alpha-Amylase characterization showed that this enzyme has high affinity with soluble starch, good hydrolysis potential and molecular weight of 116 kDa.

Adsorption↗

PubMed1987

Immunochemical analysis of baboon (Papio cynocephalus) IgG subclasses.

Few reports are presently available on the existence of IgG subclasses in nonhuman primates. Papain and trypsin digestion of baboon (Papio cynocephalus cynocephalus and P. cynocephalus hamadryas) IgG proteins, in the absence of cysteine, revealed the occurrence of two different protein populations, one being protease-resistant, the other being protease-sensitive. The papain-resistant population is rendered sensitive to digestion upon addition of cysteine. Ion exchange chromatography of the papain-resistant IgG population subsequently demonstrated that it is composed of two different subpopulations varying in their ionic binding affinities. Peptide maps of the Fc fragments of the papain sensitive population and of the Fc fragments of the two papain-resistant subpopulations differing in their binding affinities for ion exchange resins, were different from each other. The biochemical identification of the baboon IgG proteins presented here strongly suggests that they are composed of at least three different subclasses.

Animals↗

PubMed1991

Separation of mounting-inducing pheromones of vaginal mucus from estrual heifers.

There is evidence that mucus of the female bovine genital tract contains pheromones that induce physiological and behavioral responses in other animals. To study these pheromones, vaginal mucus was collected from heifers either at estrus or during diestrus. The mucus was then applied to the hindquarters of the same animal during diestrus or to the hindquarters of herdmates during diestrus. The behaviors of the treated animal and its herdmates were then observed. To attempt to isolate the mounting-inducing substance, mucus was dialyzed or separated on ion-exchange resins. Diestrous heifers to which their own estrual mucus has been applied were nearly always mounted by herdmates (P less than .01). But, heifers to which another's estrous mucus had been applied were not mounted. This suggests that vaginal mucus contains not only estrus-related pheromones, but also individual distinctive odors. The dialyzable fraction of vaginal mucus and the neutral fraction, prepared by ion-exchange chromatography of the dialyzable solution of vaginal mucus, had a mounting-inducing activity on the herdmates, as did the application of an animal's own vaginal mucus. These findings suggest that mounting-inducing pheromones are relatively low molecular weight, neutral substances.

Animals↗

PubMed1978

[Short programs for the determination of amino acids in physiological fluids (author's transl)].

Short programs for the determination of a few amino acids are described. The studies were performed with two commercially available ion exchange resins (Durrum DC6A, Phoenix XX 907 OPKU). All the programs are constructed so that they are suitable for urine analysis with unfavourable concentration ratios. The economic aspects and the areas of application of these methods are discussed.

Amino Acids↗

PubMed1976

Membrane-associated phosphatidylglycerophosphate synthetase from Escherichia coli: purification by substrate affinity chromatography on cytidine 5'-diphospho-1,2-diacyl-sn-glycerol sepharose.

The membrane-associated cytidine 5'-diphospho-1,2-diacyl-sn-glycerol (CDP-diglyceride):sn-glycerol-3-phosphate phosphatidyltransferase (EC 2.7.8.5) from Escherichia coli has been solubilized wiTriton X-100 and purified 6000-fold to 85% of homogeneity. The major purification was attained using several modifications of the the CDP-diglyceride Sepharose affinity chromatography system described by Larson et al. (Larson, T.J., Hirabayashi, T., and Dowhan, W. (1976), Biochemistry 15, 974). The native enzyme in Triton X-100 had an apparent molecular weight of over 200 000, as judged by Sepharose 6B gel filtration. The apparent size of the native enzyme appeared to be due to its association with Triton X-100, as judged by sucrose gradient centrifugation, polyacrylamide gel electrophoresis, and the lack of affinity for ion-exchange resins. The minimum subunit molecular weight of the enzyme, determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis, was 24 000. This low molecular weight is consistent with the stability of enzyme to heat, urea, or sodium dodecyl sulfate denaturation. The purified enzyme had an absolute requirement for magnesium ion (KM = 50 mM) and Triton X-100 (0.5-6%) for activity when either CDP-diglyceride or dCDP-diglyceride was used as substrate. Kinetic analysis of the enzymatic reaction indicated an ordered sequential Bi-Bi reaction with the liponucleotide forming a dead-end complex at high concentration, which inhibited both the forward and reverse reactions. The enzyme would not hydrolyze the pyrophosphate bond of its lipid substrate or the phosphate esters of its lipid product but would catalyze a cytidine 5'-monophosphate dependent exchange reaction between glycero-3-phosphate and phosphatidylglycerophosphate.

Chromatography, Affinity↗

PubMed2003

Removal of lead from contaminated water bodies using sea nodule as an adsorbent.

Adsorption of water soluble lead on polymetallic sea nodule has been studied in detail. Complete decontamination of lead is possible by appropriate sea nodule dosing. Adsorption is also dependent on pH and best adsorption is achieved at pH 6. Beyond pH 6, the desorption of lead from sea nodule surface is practically zero. Residual metal concentrations in the filtrate after adsorption is negligible. Both Freundlich and Langmuir isotherms may reasonably explain adsorption of lead on sea nodule. Chemically bound moisture plays a very crucial role in lead adsorption. Lead adsorptive capability of sea nodule is practically destroyed when calcined at a temperature of 900 degrees C. Lead loading capacity of sea nodule has been estimated at 440 mg of lead per gram of sea nodule. The performance of sea nodule as a lead adsorbent has been successfully tested over six simulated lead contaminated water systems. Lead loading capacity of sea nodule compares favorably with other adsorbents like activated carbon, ion exchange resin, anionic clay, granulated blast furnace slag and natural and treated zeolites.

Adsorption↗

PubMed2004

Determination of glycerol by gas chromatography using meso-erythritol as internal standard.

A simple chemical method for the determination of the glycerol moiety of triacylglycerols in lipids is described. The internal standard meso-erythritol is added and the mixture saponified in 0.5 M sodium hydroxide in methanol under reflux for 10 min. After cooling, the mixture is acidified with 2 M hydrochloric acid and the fatty acids extracted with hexane. The aqueous phase is then passed over a mixed cation-anion exchange resin, the eluate concentrated on the rotary evaporator below 40 [degree]C, dried overnight in a desiccator and glycerol plus meso-erythritol converted into their respective trimethylsilyl ethers by treatment with chlorotrimethylsilane and hexamethyldisilazane in pyridine. The silyl ethers are separated by capillary gas chromatography yielding the glycerol content of the lipid. As phospholipids yield mainly (>95%) glycerophosphate under our conditions of hydrolysis, which is subsequently removed by the mixed ion-exchange resin, the glycerol content is a measure of the triacylglycerol content of the original sample. A suitable correction for the presence of phospholipids can be applied by determining the phosphorus content of the lipids. In the majority of cases encountered this correction was negligible. The method is suitable for all compounds releasing glycerol on saponification, but it is especially useful for determining small amounts of triacylglycerols in an excess of wax esters. Examples of triacylglycerol determinations in the lipids of a number of South Atlantic fish species are presented.

Animals↗

PubMed1999

A prototype electrochemical chromatographic column for use with proteins.

We developed electrochemical hardware and media targeted for protein chromatography. Two types of stationary phases were investigated. The first comprised gold-plated stainless 316L beads coated with a self-assembled monolayer of 6-mercaptohexan-1-ol and was expected to behave like an ion-exchange resin in the presence of an electric field. The secondary stationary phase comprised the first stationary phase with further functionalization with immobilized heme moieties and was expected to behave like immobilized metal affinity resin. We tested apparatus with both stationary phases using ribonuclease A as a model protein and applied potentials from -0.3 to +0.3 V versus the saturated calomel electrode. Despite low binding capacities, we demonstrated that protein retention on both stationary phases could be controlled with an applied potential. The greatest extent of electromodulation was achieved with the mercaptohexanol-based ion-exchange media.

Chromatography↗

PubMed1984

Purification of three gamma-chains with different molecular weights from normal human plasma fibrinogen.

Three forms of the normal human plasma fibrinogen gamma-chain which differ in molecular weight have been purified. Plasma fibrinogen was separated by ion exchange chromatography on DEAE-Sephacel into three populations of molecules, each with a unique gamma-chain composition. Following reduction and S-carboxymethylation, the fibrinogen polypeptide chains in each chromatographic peak were separated by ion exchange chromatography on DEAE-Sephacel and identified following sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The A alpha, B beta and smallest gamma-chain (gamma 50) eluted at progressively higher ionic strengths, but the elution positions of A alpha, B beta and gamma 50 chains were identical for fibrinogen from each of the three different chromatographic fractions. The unique gamma chain of fibrinogen in the second chromatographic peak (gamma 55) eluted at an ionic strength higher than that of the gamma 50 chain, while the largest gamma-chain (gamma 57.5), which was contained only in the third chromatographic peak of fibrinogen, eluted at the highest ionic strength. The higher ionic strengths needed to elute fibrinogen in the second and third peaks was paralleled by the higher ionic strengths needed to elute the gamma-chains unique to them, suggesting that the gamma-chain composition of the three fibrinogen fractions accounted for their differential binding to the ion exchange resin. Following desialation with neuraminidase, the differences in electrophoretic mobilities between the three gamma-chain forms was maintained, indicating that differential migration on SDS-polyacrylamide gel electrophoresis was not due to variation in sialic acid content.

Chromatography, Affinity↗

PubMed2003

Development of a root feeding system based on a fiber ion-exchange substrate for space plant growth chamber "Vitacycle".

Selecting a plant root nutrient delivery system is one of the key aspects of designing root modules for space plant growth chambers. This article examines a number of the nutrient delivery systems and shows the most suitable technique for providing nutrients to roots in microgravity, which to date are ion-exchange artificial soils. In addition, this article characterizes the ion composition and hydrophysical parameters of a new Russian artificial ion charged fiber substrate, BIONA-V3. The BIONA-V3 substrate is comprised of ion-exchange resin fibers. The experimental data concerning the effects of anionic and cationic components on plant biomass is presented. Preliminary experiments with BIONA-V3 showed that 1 kg of dry BIONA-V3 produces up to 2.4 kg (fresh mass) of cabbage leaf or 180 g of dry plant mass per 1 dm3 of the substrate. Therefore, the root zone volume can be as small as 120 cm3 per plant. Further optimizing the nutrient composition of the resin fibers can increase space plant growth chamber productivity.

Biomass↗

PubMed1994

Purification procedure for bacterial translational initiation factors IF2 and IF3.

In bacteria the initiation of protein synthesis is a complex phenomenon in which specific proteins, termed initiation factors (IFs) IF1, IF2, and IF3, are involved. Notwithstanding the progress made in understanding their functions, the precise molecular mechanisms of action of these factors remain somewhat obscure. One reason for this lack of knowledge is the difficulty involved in purifying sufficient quantities of these proteins. We have developed a new procedure for purification of IFs from recombinant Escherichia coli strains producing high levels of E. coli IF3 and Bacillus stearothermophilus IF2. This new procedure is quicker than previous methods, easily scaled up to large volumes, and can be used, with only minor modifications, for different IFs. This new purification method consists essentially of one chromatographic (FPLC) separation on an ion-exchange resin (S-Sepharose fast-flow or Mono-S HR). Using this procedure we have been able to obtain chromatographically pure and biologically active preparations of both IF2 and IF3.

Bacterial Proteins↗