CM-Sephadex Ion Exchange Research Articles

English

The study investigates the purification and characterisation of rhodanese from the liver of the tilapia fish (Oreochromis niloticus) collected from Asejire Lake in Nigeria. This was with a view to understanding the biochemical basis of the survival of the fish in cyanide polluted water. Rhodanese was isolated and purified from liver tissue homogenate of tilapia using CM-Sephadex ion exchange chromatography and Sephadex G-75 gel filtration. The specific activity of the enzyme was 56.86 U/mg. The Km values for KCN and Na2S2O3 as substrates were 0.1240 ± 0.0021 mM and 0.0516 ± 0.0097 mM, respectively. The apparent molecular weight was estimated by gel filtration on a Sephacyl S-400 column to be 35,460 Da. The optimal activity was found at pH 6.5 and the temperature optimum was 40°C. The rhodanese enzyme showed that the activity of the enzyme was not affected by MgCl2, KCl, NH4Cl, MnCl2 and CaCl2 while AlCl3, inhibited the enzyme. Key words: Cyanide, detoxification, tilapia, liver, rhodanese.

Purification and Characterization of Peroxidase from Sweet Gourd (Cucurbita moschata Lam. Poiret)

Peroxidase (EC 1.11.1.7; donor: hydrogen peroxide oxidoreductase) is an oxidoreductase enzyme found in many fruits and vegetables. This enzyme was purified from sweet gourd (Cucurbita moschata Lam. Poiret) by ammonium sulphate precipitation and CM-Sephadex ion-exchange chromatography. Furthermore, optimum pH, optimum temperature, optimum ionic strength, stable pH, and stable temperature conditions were determined as 7.2, 50°C, 0.4 M, 8.0, and 40°C, respectively. The molecular weight (MW) of the enzyme was estimated to be 85 kDa by SDS-PAGE method. The values of Km and Vmax were calculated from the Lineweaver-Burk graph for guaiacol/H2O2 substrate patterns.

Purification and characterization of peroxidase from Turkish black radish (Raphanus sativus L.)

Peroxidases (EC 1.11.1.7; donor: hydrogen peroxide oxidoreductase) are part of a large group of enzymes associated with cell wall biosynthesis, response to injury, disease, resistance and wound repair. They catalyze the oxidation of various electron donor substrates such as phenols and aromatic amines in the presence of hydrogen peroxide. In the present study, peroxidase, a primer antioxidant enzyme, was purified 9.7 fold from Turkish black radish (Raphanus sativus L.) in a yield of 2% by ammonium sulphate precipitation, dialysis and CM-Sephadex ion exchange chromatography. To check the enzyme purity, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed and a single band was observed. The substrate specificity of peroxidase was investigated using guaiacol (2-methoxyphenol). Optimum pH, optimum temperature, optimum ionic strength, stable pH, stable temperature and thermal inactivation conditions were determined for guaiacol / H2O2 substrate pattern. These kinetic properties were found to be 6.0, 30°C, 1.0 M, 9.0, and 60°C, respectively. The molecular weight (Mw) of the enzyme was found to be 66 kDa by sodium dodecyl sulphatepolyacrylamide gel electrophoresis (SDS - PAGE) method. Native polyacrylamide gel electrophoresis (Native-PAGE) was performed for isoenzyme determination and a single band was observed. Km and Vmax values were calculated from Lineweaver-Burk graphs.

Purification and Characterization of Peroxidase from Cauliflower (Brassica oleracea L. var. botrytis) Buds

Peroxidases (EC 1.11.1.7; donor: hydrogen peroxide oxidoreductase) are part of a large group of enzymes. In this study, peroxidase, a primer antioxidant enzyme, was purified with 19.3 fold and 0.2% efficiency from cauliflower (Brassica oleracea L.) by ammonium sulphate precipitation, dialysis, CM-Sephadex ion-exchange chromatography and Sephadex G-25 purification steps. The substrate specificity of peroxidase was investigated using 2,2'-azino-bis(3-ethylbenz-thiazoline-6-sulphonic acid) (ABTS), 2-methoxyphenol (guaiacol), 1,2-dihydroxybenzene (catechol), 1,2,3-trihyidroxybenzene (pyrogallol) and 4-methylcatechol. Also, optimum pH, optimum temperature, optimum ionic strength, stable pH, stable temperature, thermal inactivation conditions were determined for guaiacol/H(2)O(2), pyrogallol/H(2)O(2), ABTS/H(2)O(2), catechol/H(2)O(2) and 4-methyl catechol/H(2)O(2) substrate patterns. The molecular weight (M(w)) of this enzyme was found to be 44 kDa by gel filtration chromatography method. Native polyacrylamide gel electrophoresis (PAGE) was performed for isoenzyme determination and a single band was observed. K(m) and V(max) values were calculated from Lineweaver-Burk graph for each substrate patterns.

Purification and characterization of chitosanase from Bacillus cereus D-11

A chitosanase-producing bacterium was isolated from Taiwan soils and identified as Bacillus cereus D-11 based on the biochemical properties and 16S rRNA gene sequence. The optimal medium for enzyme production consisted of 0.7% colloidal chitosan, 1% yeast extract, and 1% NaCl at an initial pH of 7.0 with 0.5% inoculation concentration (1.4 × 10 8 CFU/ml). After cultivation at 30 °C for 3 days, the maximal activity of 4.85 U/ml was observed. An extracellular chitosanase produced from B. cereus D-11 was concentrated by lyophilization and purified by Sephadex G-150 gel filtration and CM-Sephadex ion exchange column chromatography. The molecular weight of the purified chitosanase was estimated to be 41 kDa by 12.5% SDS–PAGE. The optimal pH and temperature for the chitosanase were 6.0 and 60 °C, respectively. The enzyme was stable below 50 °C and from pH 5 to 10. N-terminal amino acid sequence exhibited highest homology to the chitosanases belonging to glycoside hydrolase family 8. The enzyme was inhibited by 10 mM 2-hydroxy-5-nitrobenzyl bromide but activated by phenylglyoxal and chloramine T. The K m and V max values were 7.5 mg/ml and 2.15 × 10 −7 mol/mg/s for soluble chitosan (degree of deacetylation, DD 86%) as substrate. The D-11 chitosanase degraded chitosan with DD ranging from 70% to 100%, but did not degrade chitin. The most susceptible substrate was 86% deacetylated chitosan. Furthermore, the D-11 chitosanase inhibited the mycelial growth of Rhizoctonia solani on PDA medium.

THE PURIFICATION OF PROTEASE FROM COWSLIP (PRIMULA VERIS) AND ITS USE IN FOOD PROCESSING

Proteases perform very important functions and are used in different objectives as in vitro and in vivo. In recent years, proteases have been used for clinical, pharmaceutical and industrial applications. Most of these proteases are obtained from animal sources. News of diseases passing over from animals to human (severe acute respiratory syndrome [SARS], mad cow) has created suspicion of contamination in animal food and its product. Therefore, a new vegetal protease source for use in the food industry was studied. Ammonium sulfate fractionation and CM-sephadex ion exchange chromatography were used in the purification of the enzyme. The purified enzyme has an optimum pH of 7.0 and its optimum temperature was 70C. The Vmax and Km values determined by Lineweaver–Burk graphics were 0.44 mg/mL.min and 40 mM, respectively. The purification degree was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE ). The native molecular weight of the enzyme was 46 kDa using a gel filtration chromatograph. SDS-PAGE results show that the enzyme has two subunits, which have protease activity at 32 and 14 kD. It was investigated whether the purified and characterized protease enzyme would cause to congeal milk or could produce digestion of chicken and cow meat. The results showed that the protease enzyme can be used for industrial production.

Purification and characterization of polyphenol oxidase from nettle (Urtica dioica L.) and inhibitory effects of some chemicals on enzyme activity

Polyphenol oxidase (PPO) of nettle (Urtica dioica L.) was extracted and purified through (NH4)2SO4 precipitation, dialysis, and CM-Sephadex ion-exchange chromatography and was used for its characterization. The PPO showed activity to catechol, 4-methylcatechol, L-3,4-dihydroxyphenylalanine (L-DOPA), L-tyrosine, p-cresol, pyrogallol, catechin and trans-cinnamic acid. For each of these eight substrates, optimum conditions such as pH and temperature were determined and L-tyrosine was found to be one of the most suitable substrates. Optimum pH and temperature were found at pH 4.5 and 30°C respectively and Km and Vmax values were 7.90 × 10−4 M, and 11290 EU/mL for with L-tyrosine as substrate. The inhibitory effect of several inhibitors, L-cysteine chloride, sodium azide, sodium cyanide, benzoic acid, salicylic acid, L-ascorbic acid, glutathione, thiourea, sodium diethyl dithiocarbamate, β-mercaptoethanol and sodium metabisulfite were tested. The most effective was found to be sodium diethyl dithiocarbamate which acted as a competitive inhibitor with a Ki value of 1.79 × 10−9 M. In addition one isoenzyme of PPO was detected by native polacrylamide slab gel electrophoresis.

Occurrence of a unique protein toxin from the Indian King Cobra ( Ophiophagus hannah) venom

A unique (lethal–cardiotoxic–hemorrhagic) protein toxin (Toxin CM55) was isolated and purified from Indian King Cobra ( Ophiophagus hannah) venom by CM-sephadex ion exchange chromatography and reverse phase HPLC. The purified toxin had an SDS-molecular weight of 22 ± 0.5 kD. UV absorption spectra of Toxin CM55 showed a peak at 280 nm, whereas when excited at 280 nm fluorescence, Toxin CM55 showed an E max at 333.4 nm. Toxin CM55 had an LD 50 of 28.28 μg/20 g (i.v.) in albino mice. The cardiotoxic action of the toxin was established on isolated guinea pig/rabbit heart and guinea pig auricle. In rats, Toxin CM55 caused ECG abnormalities including widened QRS complex and monomorphic ventricular tachycardia suggesting that the possible site of action of Toxin CM55 was the ventricle. Toxin CM55 produced significant vasoconstriction on peripheral blood vessels. It produced significant contraction of isolated guinea pig ileum, rat fundus and rat uterus, which was completely antagonised by methysergide. The toxin was found to release a significant amount of serotonin from rabbit platelets. Toxin CM55 produced cutaneous hemorrhage in albino mice, which was also produced in reserpine and p-chloro phenylalanine pretreated animals. Rabbit antiserum was raised against Toxin CM55, which gave prominent bands in immunogel diffusion and immunoelectrophoresis. The antiserum provided 2 LD 50 protection against Toxin CM55-induced lethality in mice and also neutralised 3 MHD hemorrhagic dose of the toxin.

Molecular characteristics of the inhibition of human neutrophil elastase by nonsteroidal antiinflammatory drugs.

Nonsteroidal antiinflammatory drugs(NSAIDs) are known as clinically effective agents for treatment of inflammatory diseases. Inhibition of cyclooxygenase has been thought to be a major facet of the pharmacological mechanism of NSAIDs. However, it is difficult to ascribe the antiinflammatory effects of NSAIDs solely to the inhibition of prostaglandin synthesis. Human neutrophil elastase (HNElastase; HNE, EC 3.4.21.37) has been known as a causative factor in inflammatory diseases. To investigate the specific relationship between HNElastase inhibition and specificity of molecular structure of several NSAIDs, HNElastase was purified by Ultrogel AcA54 gel filtration, CM-Sephadex ion exchange, and HPLC (with TSK 250 column) chromatography. HNElastase was inhibited by aspirin and salicylate in a competitive manner and by naproxen, ketoprofen, phenylbutazone, and oxyphenbutazone in a partial competative manner, but not by ibuprofen and tolmetin. HNElastase-phenylbutazone-complex showed strong Raman shifts at 200, 440, 1124, 1194, 1384, 1506, and 1768 cm(-1). The Raman bands 1194, 1384, and 1768 cm(-1) may represent evidences of the conformational change at -N=N-phi radical, pyrazol ring, and -C=O radical of the elastase-drug complex, respectively. Phenylbutazone might be bound to HNElastase by ionic and hydrophobic interaction, and masked the active site. Inhibition of HNElastase could be another mechanism of action of NSAIDs besides cyclooxygenase inhibition in the treatment of inflammatory diseases. Different inhibition characteristics of HNE-lastase by NSAIDs such as aspirin, phenylbutazone-like drugs and ineffective drugs could be important points for drawing the criteria for appropriate drugs in clinical application.

Catalytic and physico-chemical characteristics of goat spleen cathepsin B.

To improve the level of purity of cathepsin B, we have modified the published procedure [Agarwal, S.K. and Khan, M.Y. (1987) Biochem. Int. 15,785-792] by incorporating CM-Sephadex ion exchange chromatography and chromatofocusing. The enzyme thus isolated could be resolved into one 26 kDa major and a minor 27 kDa protein bands on SDS-PAGE. The two components, however, could not be separated by gel filtration and they eluted, in a single peak corresponding to a molecular mass of 28.1 kDa. Among the various substrates tested, Z-Phe-Arg-MCA with a Km of 0.058 mM and hemoglobin with a Km of 1.449 microM were the most preferred synthetic and protein substrates respectively. It was found to be a glycoprotein with an acidic pI of 4.8. The enzyme was activated by various thiol-reducing reagents and inhibited by cysteine proteinase inhibitors, divalent cations, lysyl group modifiers, anti-inflammatory drug and denaturing agents. The hydrodynamic behaviour of cathepsin B suggested a compact and globular conformation. Immunodiffusion studies with anti-goat cathepsin B indicated a tissue/ species dependence.

Purification and biologic properties of fibroblast somatomedin.

Cultured human fibroblasts produce a peptide growth factor that cross-reacts with antisera to human somatomedin-C (Sm-C). To determine the identity of this species and compare its molecular properties to pure Sm-C, 2 liters of conditioned medium derived from human fibroblast monolayers were concentrated (X10) by ultrafiltration. The concentrated conditioned medium was purified further by CM-Sephadex ion-exchange chromatography. Following elution in 1.0 M NaCl, pH 8.0, the active material was purified by gel filtration on Sephadex G-150. The active fractions which eluted at Kd 0.45 (Mr estimated at 32,000) were further purified by isoelectric focusing. Two peaks of activity electrofocused at pI 5.4 and 7.2, respectively. The pI 5.4 peak contained only binding protein activity. The active fractions from the neutral pool were further purified by reverse-phase high pressure liquid chromatography on a C-18 Bondapak with a linear gradient of acetonitrile (10-60%). The active single peak which eluted at 55% acetonitrile gave a single band when analyzed by polyacrylamide gel electrophoresis. This material stimulated [3H]thymidine incorporation into human fibroblast DNA with approximately 3.2 times the potency of pure Sm-C but was equipotent in stimulating BALB/c 3T3 fibroblasts. It was degraded by fibroblast cultures at a slower rate compared to Sm-C, although it had a similar affinity for Sm-C-binding protein. We conclude that human fibroblasts produce two peptides that react with anti-Sm-C antibody but are chemically distinct from Sm-C. The greater response to fibroblast somatomedin may be due to its affinity for somatomedin-binding protein and slower degradation. These findings may have implications for understanding the regulation of human fibroblast replication.

A plasminogen activator from benign ovarian cystadenoma: Partial purification and characterization

A plasminogen activator has been partially purified from benign serous cystadenomas by a combination of Sephadex G-200 gel filtration, CM-Sephadex ion exchange, Concanavalin A-Sepharose and arginine-Sepharose affinity chromatographies. Its apparent size was very large and could not penetrate Sepharose 6B or 5% SDS polyacrylamide gel. It hydrolyzed plasminogen in a manner similar to that of urokinase in terms of their apparent Michaelis constants, although a one-minute lag period had to be allowed for this activation before the hydrolysis of plasminogen. It was very sensitive to reducing agent such that 5 mM dithiothreitol could completely destroy its activity. The activator crossreacted with anti-uterine plasminogen activator IgG, but did not react with anti-urokinase at all. It also bound fibrin well. In the absence of plasminogen, the activator was devoid of amidolytic activity towards S-2251, S-2302 and S-2288 but had a small but measurable activity against S-2444.

Purification and amino acid analysis of cytochrome c fromUstilago violacea

Cytochrome c fromUstilago violacea was further analyzed in order to characterize the pink phenotype. NaOH-extracted cytochrome c was purified in three steps, which included ammonium sulfate precipitation, CM-Sephadex ion-exchange chromatography with 0.5 N NaCl elution, and CM-Sephadex ion-exchange chromatography with a 0.0–0.6 N NaCl gradient elution. Polyacrylamide gel electrophoresis of the purified protein yielded a single red band, which was the only band detected upon Coumassie brilliant blue staining. HCl-hydrolysates of the protein were examined for their amino acid composition, which indicated that the cytochrome c fromU. violacea contains approximately 104 residues, with high levels of alanine, histidine, serine, and low levels of phenylalanine and arginine.

Studies of acetylation and deacetylation in high mobility group proteins. Identification of the sites of acetylation in high mobility group proteins 14 and 17.

Duck erythrocytes were incubated with [3H]acetate both in the presence and absence of sodium butyrate. Subsequent perchloric acid extraction of the nuclei, followed by selective acetone precipitation, CM-Sephadex ion exchange chromatography, and gel filtration yielded radioactively labeled high mobility group (HMG) proteins HMG-14 and HMG-17 in pure form. Extensive enzymatic degradation of the proteins followed by amino acid analysis of the digests yielded a significant amount of material eluting in the position of epsilon-N-acetyllysine. Furthermore, automated Edman degradation of intact 3H-labeled HMG-14 and HMG-17 identified the specific sites of acetylation of these proteins. In both erythrocyte HMGs isolated from cells not exposed to butyrate, the lysine residue at position 2 was the only one found to be labeled. However, one additional site in HMG-14 and two additional sites in HMG-17 were found in the proteins from cells incubated in butyrate. Finally, studies of the enzymatic deacetylation of HMG-14 and HMG-17 confirmed that both nuclear proteins serve as deacetylase substrates and that butyrate inhibits their deacetylation, just as in the case of other HMG proteins and nucleosomal core histones.

Human helper T cell factor(s) (ThF). I. Partial purification and characterization.

T cells obtained from pleural effusion of patients with tuberculous pleurisy were stimulated in vitro with PPD. The culture supernatant was shown to be substituted for T cells in PWM-induced IgG production by human B cells. As many as 0.5 to 3 x 10(9) lymphocytes were obtained from 1 patient, and about 85% of them were E-rosette positive, making it possible to purify human helper T cell factor(s) (ThF). Helper activity was sensitive to heating at 70 degrees C for 5 min and treatment with trypsin. ThF did not have conventional Ig determinants and was recovered in the 50 to 67% ammonium sulfate fraction. The purification was done by successive DEAE-Sephadex and CM-Sephadex ion-exchange chromatography, Sephadex G-100 gel filtration, and isoelectric focusing. It was shown that ThF activity was eluted by gel filtration in the fraction with a m.w. of about 20,000. Isoelectric focusing of this fraction revealed that ThF activity distributed in the pl range of 6.5 to 8.0, whereas TCGF activity was focused in a single peak at pI of 6.5, indicating the existence of a helper factor without TCGF activity.

Glycocinnamoylspermidines, a new class of antibiotics. II. Isolation, physiocochemical and biological properties of LL-BM123beta, gamma1 and gamma2.

LL-BM123beta, gamma1 and gamma2 are three new antibiotics produced by fermentation of an unidentified species of Nocardia. These strongly basic, water soluble compounds were isolated from the culture filtrate by CM-Sephadex ion-exchange and carbon chromatography. All three antibiotics are active against both gram-positive and gram-negative bacteria. A mixture of LL-BM123 gamma1 and gamma2 is more active than the beta component but generally less active than gentamicin.