Purification and properties of a fibrinolytic enzyme from Bacillus subtilis

A fibrinolytic enzyme obtained from B. subtilis was purified, using DEAE-cellulose column chromatography, and gel filtration on Sephadex G-100. The preparation was homogeneous as tested by gel filtration on Sephadex G-200, and disc electrophoresis. The molecular weight of this enzyme was 29.400 estimated by gel filtration on Sephadex G-100. The optimum pH for enzyme activity was 7.2 Copper ions significantly increased enzyme activity, while Zn++ and Mn++ caused marked inhibition.     

Peptidoglutaminase-I and II: Isolation in Homogeneous Form

Peptidoglutaminase-I and II that catalyzed the hydrolysis of the γ-amide of peptidebound glutamine, were purified from the cell-free extracts of Bacillus circulans by streptomycin sulfate precipitation, ammonium sulfate fractionation, DEAE-Sephadex, Sephadex G-200, QAE-Sephadex, hydroxylapatite-cellulose column chromatography, and finally preparative polyacrylantide gel disc electrophoresis. The purification steps resultd in a 714-fold increase in specific activity for peptidoglutaminase-I and in a 223-fold for peptidoglutaminase-II over the original extracts. The both enzymes were homogeneous in disc electrophoresis in polyacrylamide gel, immunoelectrophoresis in agar gel, and sedimentation analysis. Using gel filtration, the molecular weights of peptidoglutaminases I and II were estimated to be 90,000 and 125,000. However, during the purification steps, the both enzymes were observed to cause the dissociation and aggregation reaction which did not so much affect on their enzyme activities.     

Purification and properties of oxytocinase (cystine amino-peptidase) from monkey placenta.

Oxytocinase (cystyl-aminopeptidase) [EC 3.4.11.3] was isolated from monkey placenta in a purified form by a six-step prodedure comprising extraction from monkey placenta homogenate, ammonium sulfate fractionation, repeated chromatography on hydroxylapatite, chromatography on a column of DEAE-cellulose and gel filtration on a column of Sephadex G-200. The purified enzyme showed a single band on polyacrylamide disc electrophoresis. Oxytocin was inactivated by this enzyme preparation. The enzyme hydrolyzed several aminoacyl-beta-naphthylamides. A terminal amino group was required for enzyme activity. The molecular weight of the purified enzyme was estimated to be 87,000 by gel filtration and 83,000 by sodium dodecyl sulfate gel electrophoresis. Other properties of the enzyme, the effects of metal ions and various chemical reagents on the enzyme activity, the pH optimum, and Km values for a number of aminoacyl-beta-naphthylamides were also examined.     

Brain pyridoxal kinase. Purification and characterization

Pyridoxal kinase has been purified 9000-fold from sheep brain. The purification procedure involves ammonium sulphate fractionation, DEAE-cellulose chromatography, affinity chromatography and Sephadex G-100 gel filtration. The final chromatography step yields a homogeneous preparation of high specific activity with a pI of 5. The molecular mass of the native enzyme was estimated to be approximately 80 kDa by 10-25% gradient polyacrylamide gel electrophoresis and Sephadex G-200 gel filtration. The subunit molecular mass was determined by sodium dodecyl sulphate (SDS)/polyacrylamide gel electrophoresis to be 40 kDa compared with a series of molecular mass standards. This indicates that pyridoxal kinase is a dimeric enzyme. Further results obtained from electron microscopy, using a negative staining technique, provide evidence that pyridoxal kinase exists as a dispherical subunit structure.     

Purification and properties of L-asparaginase from Mycobacterium phlei.

1. L-asparaginase from M. phlei was purified about 170-fold with an 11% yield. The purification procedure consisted of: fractionation with ammonium sulphate; adsorption of contaminating proteins on calcium phosphate gel; chromatography on Sephadex G-150 and DEAE-cellulose. The specific activity of the final preparation was 32.6 i.u./mg protein. 2. Molecular weight of the enzyme as determined by Sephadex G-100 filtration amounted to 126 000. Optimum pH was 8.8-9.2. The enzyme did not hydrolyse L-glutamine over the pH range 4-9, and was inhibited by D-asparagine. The apparent Michaelis constant for L-asparagine was 0.7 mM; energy of activation, 9800 cal/mole. 3. On polyacrylamide-gel electrophoresis the final preparation revealed two protein bands, one of which was coincident with the enzyme activity.     

Isolation of L-dynurenine 3-hydroxylase from the mitochondrial outer membrane of rat liver.

Outer membrane preparations of rat liver mitochondria were isolated, after the mitochondria had been prepared by mild digitonin treatment under isotonic conditions. L-Kynurenine 3-hydroxylase [EC 1.14.13.9] was solubilized on a large scale from outer membrane by mixing with 1% digitonin or 1% Triton X-100, followed by fractionation into a minor fraction I and a major fraction II by DEAE-cellulose column chromatography. The distribution of total L-Dynurenine 3-hydroxylase was roughly 20 and 80% in fraction I and II, respectively. Fraction I consisted of crude enzyme loosely bound to anion exchanger. In the present investigation, fraction I was not used because of its low activity and rapid inactivation. In contrast, fraction II consisted of crude enzyme with high activity, excluded from DEAE-cellulose column chromatography in the presence of 1 M KC1. In addition, fraction II was purified by Sephadex G-200 gel filtration and DEAE-Sephadex A-50 column chromatography with linear gradient elution, adding 1 M KC1 and 1% Triton X-100 to 0.05 M Tris-acetate buffer, pH 8.1. After isoelectric focusing, the purified enzyme preparation was proved to be homogeneous, since the L-kynurenine 3-hydroxylase fraction gave a single band on disc gel electrophoresis. The molecular weight of this enzyme was estimated to be approximately 200,000 or more by SDS-polyacrylamide gel electrophoresis and from the elution pattern on Sephadex G-200 gel filtration. A 16-Fold increase of the enzyme activity was obtained compared with that of the mitochondrial outer membrane. The isoelectric point of the enzyme was determined to be pH 5.4 by Ampholine isoelectric focusing.     

Isolation and characterization of a sulfated glycoprotein from rabbit uterus.

Crude glycoproteins were extracted with 0.15 M NaCl from the pooled endometrial scrapings of rabbit uteri after treatment with estrogen. The crude glycoproteins were fractionated with ammonium sulfate, followed by DEAE-cellulose column chromatography, treatment with CM-Sephadex C-25 and gel filtration on Sephadex G-200. Subsequently, purification of an acidic glycoprotein was carried out by gel filtration on Sephadex G-200 and then Sepharose 4B. The results of electrophoresis and enzymatic digestion, together with analytical data and the infrared spectrum indicated that the acidic glycoprotein was a sulfated glycoprotein.     

Multiple proteins related to the soluble galactose-binding animal lectin revealed by a monoclonal anti-lectin antibody.

An enzyme catalysing the O-methylation of isobutyraldoxime by S-adenosyl-L-methionine was isolated from Pseudomonas sp. N.C.I.B. 11652. The enzyme was purified 220-fold by DEAE-cellulose chromatography, (NH4)2SO4 fractionation, gel filtration on Sephadex G-100 and chromatography on calcium phosphate gel. Homogeneity of the enzyme preparation was confirmed by isoelectric focusing on polyacrylamide gel and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The enzyme showed a narrow pH optimum at 10.25, required thiol-protecting agents for activity and was rapidly denatured at temperatures above 35 degrees C. The Km values for isobutyraldoxime and S-adenosyl-L-methionine were respectively 0.24 mM and 0.15 mM. Studies on substrate specificity indicated that attack was mainly restricted to oximes of C4-C6 aldehydes, with preference being shown for those with branching in the 2- or 3-position. Ketoximes were not substrates for the enzyme. Gel filtration on Sephadex G-100 gave an Mr of 84 000 for the intact enzyme, and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis indicated an Mr of 37 500, suggesting the presence of two subunits in the intact enzyme. S-Adenosylhomocysteine was a powerful competitive inhibitor of S-adenosylmethionine, with a Ki of 0.027 mM. The enzyme was also susceptible to inhibition by thiol-blocking reagents and heavy-metal ions. Mg2+ was not required for maximum activity.     

Partial purification and characterization of glycylprolyl dipeptidyl aminopeptidase in porcine pancreas

This study reports the presence of glycylprolyl dipeptidyl aminopeptidase in porcine pancreas, and its partial purification and some properties. Crude enzyme preparation was obtained by extraction from acetone-dried powder of the pancreas at pH 7.6. For solubilization of enzyme, freezing and thawing were carried out. Crude enzyme extract was fractionated with ammonium sulfate precipitation, gel filtration on Sephadex G-200 column and ion-exchange chromatography on DEAE-cellulose. Partially purified enzyme showed 2897-folds purification. The enzyme activity on polyacrylamide gel electrophoresis showed good agreement with a main protein band stained with Coomassie brilliant blue. Molecular weight of this enzyme from the pancreas was estimated to be 300 000 by gel filtration on Sephacryl S-300 column. Optimum pH was between 8.5 and 9.0, and K_m value for glycylproline-p-nitroanilide tosilate was 0.33 mM. This enzyme from the pancreas was a serine enzyme and was relatively stable to heat at 60°C for 10 min.     

Purification of 7 alpha-hydroxysteroid dehydrogenase from Escherichia coli strain 080

Purification studies of 7 alpha-hydroxysteroid dehydrogenase (7 alpha-HSDH) (EC 1.1.1.159) from Escherichia coli 080 showed that 1.59-fold purification could be achieved by heating (60 degrees C for 10 min) the ultracentrifuged enzyme preparation, and 6.46-fold purification was achieved by subsequent precipitation with ammonium sulfate. Further purification on Sephadex G-100 gel gave 10.1-fold purification. After pooling and concentrating the active fractions obtained from the Sephadex G-100 filtration, an 11.1-fold purification was achieved using DEAE-cellulose chromatography. The purified enzyme produced a single band on polyacrylamide gel electrophoresis and its molecular weight was determined to be 54,000. The enzyme was immunogenic and showed immunoprecipitation with homologus antisera.     

Purification and properties of pyridoxal kinase from bovine brain

A 27,000-fold purification of pyridoxal kinase from bovine brain tissue has been achieved by a combination of ammonium sulfate fractionation, DEAE-cellulose chromatography, hydroxyapatite chromatography, Sephadex G-150 gel filtration, Blue Sepharose CL-6B chromatography, and Phenyl-Superose chromatography. The final chromatography step yields a homogeneous preparation of high specific activity (2105 nmol/min/mg protein). The molecular mass of the native enzyme was estimated to be approximately 80,000 on gel filtration. The subunit molecular mass was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis to be approximately 39,500. This indicates that pyridoxal kinase is a dimeric enzyme.     

Human blood group glycosyltransferase. II. Purification of galactosyltransferase

A galactosyltransferase, which converts blood group O red bloodcells to B-cells, was purfied to homogeneity from plasma of blood group B subjects. The stepwise purification procedures include: (a) column chromatography with CM-Sephadex, followed by ammonium sulfate fractionation; (b) Sephadex G-200 gel filtration; (c) column chromatogr,phy with DEAE-Sephadex; and (d) column chromatography with hydroxylapatite. The procedures provided about a 400,000-fold increase of specific activity with a 40 to 50% yield. Further purification of the enzyme was performed by small scale preparative acrylamide gel electrophoresis at pH 4.3. The final enzyme preparation showed a single protein band which coincided with enzyme activity, in acrylamide gel electrophoresis, and revealed a single protein band in sodium dodecyl sulfate-gel electrophoresis. Judging from the molecular weight, which was estimated by Sephadex gel filtration, and subunit size estimated by sodium dodecyl sulfate-gel electrophoresis, the enzyme is presumably in a dimeric form. The enzyme required Mn2+ for its activity and had a pH optimum at 7.0 to 7.5.     

Purification of 6-phosphogluconate dehydrogenase from chicken liver and investigation of some kinetic properties

6-phosphogluconate (6PG) dehydrogenase (EC 1.1.1.44; 6PGD) was purified from chicken liver; some kinetic and characteristic properties of the enzyme were investigated. The purification procedure consisted of four steps: preparation of the hemolysate, ammonium sulfate precipitation, 2',5'-ADP Sepharose 4B affinity chromatography, and Sephadex G-200 gel filtration chromatography. Thanks to the four consecutive procedures, product having a specific activity of 61 U (mg proteins)(-1), was purified 344-fold with a yield of 5.57%. Optimum pH, stable pH, optimum temperature, and KM and Vmax values for NADP+ and 6PG substrates were determined for the enzyme. Molecular weight of the enzyme was also determined by Sephadex G-200 gel filtration chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). In addition, Ki values and inhibition types were estimated by means of Lineweaver-Burk graphs obtained for NADPH and CO2 products.     

Differences between newly formed and recycled free small ribosome subunits in liver cytoplasm.

1. Ferritin has been isolated from the serum of four patients with iron overload by using two methods. 2. In method A, the serum was adjusted to pH 4.8 and heated to 70 degrees C. After removal of denatured protein, ferritin was concentrated and further purified by ion-exchange chromatography and gel filtration. In most cases, only a partial purification was achieved. 3. In method B, ferritin was extracted from the serum with a column of immuno-adsorbent [anti-(human ferritin)] and released from the column with 3M-KSCN. Further purification was achieved by anion-exchange chromatography followed by the removal of remaining contaminating serum proteins by means of a second immunoadsorbent. Purifications of up to 31 000-fold were achieved, and the homogeneity of the final preparations was demonstrated by polyacrylamide-gel electrophoresis. 4. Serum ferritin purified by either method has the same elution volume as human spleen ferritin on gel filtration on Sephadex G-200. Serum ferritin has a relatively low iron content and iron/protein ratios of 0.023 and 0.067 (mug of Fe/mug of protein) were found in two pure preparations. On anion-exchange chromatography serum ferritin has a low affinity for the column when compared with various tissue ferritins. Isoelectric focusing has demonstrated the presence of a high proportion of isoferritins of relatively high pI. 5. Possible mechanisms for the release of ferritin into the circulation are briefly discussed.     

Studies of human kidney gamma-glutamyl transpeptidase. Purification and structural, kinetic and immunological properties.

gamma-Glutamyl transpeptidase, present in various mammalian tissues, transfers the gamma-glutamyl moiety of glutathione to a variety of acceptor amino acids and peptides. This enzyme has been purified from human kidney cortex about 740-fold to a specific activity of 200 units/mg of protein. The purification steps involved incubation of the homogenate at 37 degrees followed by centrifugation and extraction of the sediment with 0.1 M Tris-HCl buffer, pH 8.0, containing 1% sodium deoxycholate; batchwise absorption on DEAE-cellulose; DEAE-cellulose (DE52) column chromatography; Sephadex G-200 gel filtration; and affinity chromatography using concanavalin A insolubilized on beaded Agarose. Detergents were used throughout the purification of the enzyme. The purified enzyme separated into three protein bands, all of which had enzyme activity, on polyacrylamide disc electrophoresis in the presence of Triton X-100. The enzyme has an apparent molecular weight of about 90,000 as shown by Sephadex G-200 gel filtration, and appears to be a tetramer with subunits of molecular weights of about 21,000. The Km for gamma-glutamyl transpeptidase using the artificial substrate, gamma-glutamyl-p-nitroanilide, with glycylglycine as the acceptor amino acid was found to be about 0.8 mM. The optimum pH for the enzyme activity is 8.2 and the isoelectric point is 4.5. Both GSH and GSSG competitively inhibited the activity of gamma-glutamyl transpeptidase when gamma-glutamyl-p-nitroanilide was used as the substrate. Treatment of the purified enzyme with papain has no effect on the enzyme activity or mobility on polyacrylamide disc electrophoresis. The purified gamma-glutamyl transpeptidase had no phosphate-independent glutaminase activity. The ratio of gamma-glutamyl transpeptidase to phosphate-independent glutaminase changed significantly through the initial steps of gamma-glutamyl transpeptidase purification. These studies indicate that the transpeptidase and phosphate-independent glutaminase activities are not exhibited by the same protein in human kidney.     

Purification of a Ca2+-activatable cyclic nucleotide phosphodiesterase from bovine heart by specific interaction with its Ca2+-dependent modulator protein.

A Ca2+-activatable cyclic nucleotide phosphodiesterase from bovine heart can be eluted from a DEAE-cellulose column either in the free form by buffers containing 0.1 mM ethylene glycol bis(beta-aminoethyl ether)N-N,N'N'-tetraacetic acid (EGTA) or as a complex of the enzyme with its protein modulator by buffers containing 0.01 mM CaCl2. A purification procedure based primarily on the significantly different affinity of the two forms of the enzyme for DEAE-cellulose was developed for the purification of the enzyme from bovine heart. The procedure involves ammonium sulfate fractionation, three chromatographic steps on DEAE-cellulose, and gel filtration on Sephadex G-200 with a 5000-fold purification over the crude extract. The purified enzyme has a specific activity of 120 mumol of cAMP/mg/min, can be activated 5-fold by Ca2+, but is only 80% pure as judged by analytical disc gel electrophoresis. The purified enzyme is unstable but can be stabilized by addition of Ca2+ and the protein modulator; this is in contrast to the less pure preparations of Ca2+-activatable phosphodiesterase which are destabilized by the protein modulator in the presence of Ca2+.     

Purification and some properties of trehalase from Chaetomium aureum MS-27

The trehalase of Chaetomium aureum was purified about 196-fold with a yield of 51% from the culture filtrate by ammonium sulfate fractionation, DEAE-cellulose column chromatography, acetone fractionation, and Sephadex G-100 gel filtration. The enzyme preparation was homogeneous on disc electrophoresis. The enzyme was most active at pH 4.0 and 50°C. The enzyme was stable from pH 4.0 to 9.0 on 12 h incubation at 37°C. The molecular weight of the enzyme was estimated to be 450,000 by gel filtration on a column of Sepharose 6B, and 115,000 by SDS polyacrylamide gel electrophoresis. This indicated that the enzyme might consist of 4 subunits. The isoelectric point of the enzyme was pH 4.0. The enzyme was active specifically on trehalose and not active on the other disaccharides tested.     

Isolation and some properties of NAD+ reductase of the green photosynthetic bacterium Prosthecochloris aestuarii.

NAD+ reductase of the green photosynthetic bacterium Prosthecochloris aestuarii was isolated and purified by ammonium sulfate fractionation, DEAE-cellulose column chromatography, and Sephadex G-200 gel filtration. This enzyme is an FAD-containing flavoprotein and has absorption maxima at 485 (shoulder0 452, 411, and 385 nm (the 411 nm band is due to cytochrome). The molecular weight of the enzyme as determined by gel filtration using Sephadex G-200 is 119,000. The enzyme catalyzes the reduction of NAD+ and NADP+ by photoreduced spinach ferredoxin or reduced benzyl viologen...     

Affinity purification and some molecular properties of human liver alkaline phosphatase.

Alkaline phosphatase from human liver was purified to homogeneity. The purification procedure included solubilization with butanol, fractionation with acetone, and chromatography on concanavalin A-Sepharose, DEAE-cellulose, Sephadex G-200 and DEAE-Sephadex. Purity was established by standard and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The isoelectric point of the protein was determined to be 4.0. Sephadex-gel filtration gave a mol.wt. of 146000, although a higher value was obtained in the presence of 100mM-NaC1. The subunit mol.wt. 76700, was determined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Neuraminidase treatment resulted in two enzyme-activity bands on isoelectric-focused gels with isoelectric points of 6.6 and 6.8. The desialylated enzyme gave only one protein band on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis with a subunit molecular weight indistinguishable from that of the non-neuraminidase-treated protein. The desialylated enzyme was more readily denatured by sodium dodecyl sulphate in the presence of mercaptoethanol than was the native enzyme.     

Purification of N-hydroxy-2-acetylaminofluorene reductase from rabbit liver cytosol

N-Hydroxy-2-acetylaminofluorene reductase was purified from rabbit liver cytosol by fractionation with ammonium sulfate, and chromatography with DEAE-cellulose, Sephadex G-200 and hydroxylapatite. The purified enzyme was homogeneous by the criterion of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weight of the enzyme was estimated to be 34,000 by the electrophoresis and by gel filtration on Sephadex G-200. The enzyme required cysteine, glutathione, dithiothreitol, 2-mercaptoethanol, NADPH or NADH as an electron donor. The enzyme activity was inhibited by p-chloromercuribenzoic acid, N-ethylmaleimide, cupric sulfate or disulfiram, but little by oxygen.