Purification and properties of chorismate synthase from Bacillus subtilis.

Chorismatic synthase was purified to apparent homogeneity from Bacillus subtilis. The enzyme required NADPH-dependent flavin reductase, Mg2+, NADPH, and flavin (FMN or FAD) for activity. The molecular weight of chorismate synthase was 24,000 as determined by sodium dedecyl sulfate (SDS)-gel electrophoresis. The enzyme was also isolated in a complex form associated with NADPH-dependent flavin reductase and another enzyme of the aromatic amino acid pathway, dehydroquinate synthase. On SDS-gel electrophoresis, this form was resolved into three bands with molecular weights of 13,000, 17,000, and 24,000. The enzyme complex was easily dissociated and the dissociation resulted in a change in the chromatographic properties of NADPH-dependent flavin reductase which was no longer retained on phosphocellulose whereas chorismate synthase was still adsorbed. Chorismate synthase activity was linear with time and protein concentration, whereas partially purified preparations showed a significant lag period before the reaction took place. Moreover, crude or partially purified enzyme preparations were completely inactivated by dilution and the activity could be recovered by addition of flavin reductase. A possible role of NADPH-dependent flavin reductase in the activation and regulation of chorismate synthase activity is discussed.     

Purification and properties of mannanase from Bacillus subtilis

Extracellular mannanase from Bacillus subtilis NM-39, an isolate from Philippine soil, was purified about 240-fold with a yield of 7.3% by ammonium sulphate fractionation, DEAE-Toyopearl chromatography and Sephacryl S-200 gel filtration. Its M _r was 38 kDa and it had a pI of 4.8 and optimum activity at pH 5.0 and 55°C. It was stable at pH 4 to 9 and below 55°C. The amino acid composition of the enzyme was in the order Gly>Glx>Ser and Asx>Ala.N.S. Mendoza and L.M. Joson are with Industrial Technology Development Institute, Department of Science and Technology, Manila, Philippines. M. Arai and T. Kawaguchi are with Department of Agricultural Chemistry, College of Agriculture, University of Osaka Prefecture, Sakai, Osaka 593, Japan; T. Yoshida is with Faculty of Engineering, Osaka University, Suita, Osaka 565, Japan.     

Purification and properties of a manganese-stimulated endonuclease from Bacillus subtilis.

An endonuclease stimulated by manganese or calcium ions was isolated from Bacillus subtilis. This enzyme attacked double- or single-stranded deoxyribonucleic acid from a variety of sources, including B. subtilis, and was purified from the material released into the medium during protoplast formation. The enzyme appeared as a single peak after glycerol gradient centrifugation and comprised approximately 30 to 35% of the protein in the most purified preparations, as estimated by gel electrophoresis. It had a molecular weight of about 46,000. The mode of action of the enzyme was endonucleolytic, and circular deoxyribonucleic acid was readily cleaved. The enzyme introduced a limited number of both double- and single-strand breaks into native deoxyribonucleic acid, generally yielding products of 1 X 10(6) daltons or more in size. The reasons for this limitation of cleavage were not clear. The activity of the enzyme was inhibited by low levels of Cu2+, Co2+, Hg2+, and Zn2+. It was also inhibited by high concentrations of NaCl. A role for this enzyme in bacterial transormation is suggested.     

Purification and properties of GTP-cyclohydrolase from Bacillus subtilis]

Highly purified GTP-cyclohydrolase was obtained by fractionation of cell extracts with ammonium sulfate, ion-exchange and hydrophobic chromatography. The N-terminal amino acid sequence and amino acid composition of the protein were determined. According to SDS-PAGE data, the molecular weight of the enzyme is 45 kDa. The active enzyme has several isoforms separable by native electrophoresis. The maximal enzyme activity is determined at 1.5 mM Mn2+; 70% of enzymatic activity is detected with Mg2+. The enzyme is inhibited by heavy metal ions and chelators and is inactive in the absence of thiol-reducing agents. The enzyme activity is detected in a broad range of pH with a maximum at pH 8.2. The pyrimidine product of the GTP-cyclohydrolase reaction. 2.5-diamino-6-hydroxy-4-ribosylaminopyrimidine-5'-phosphate was purified and identified. Another product of this reaction is pyrophosphate.     

Purification and properties of Bacillus subtilis inositol dehydrogenase.

Inositol 2-dehydrogenase (EC 1.1.1.18) activity appears during growth of Bacillus subtilis (strain 60015) in nutrient sporulation medium. Its synthesis is induced by myo-inositol and repressed by D-glucose. The enzyme has an apparent molecular weight of 155,000 to 160,000 as determined by sucrose density gradient centrifugation, and it is comprised of four subunits, each having a molecular weight of 39,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point of the enzyme is 4.4 as determined by column isoelectric focusing. The enzyme shows the highest Vmax and lowest Km with myo-inositol as substrate but does not react with scyllo-inositol; it also reacts with the alpha anomer (but not the beta anomer) of D-glucose and with D-xylose. Apparently, the enzyme can remove only the single equatorial hydrogen of the cyclitol or pyranose ring. In contrast to the glucose dehydrogenase of spores, which reacts with D-glucose or 2-deoxy-D-glucose and with NAD or NADP, inositol dehydrogenase requires NAD and does not react with 2-deoxy-D-glucose.     

Purification and properties of Bacillus subtilis aspartate transcarbamylase.

Aspartate transcarbamylase from Bacillus subtilis has been purified to apparent homogeneity. A subunit molecular weight of 33,500 +/- 1,000 was obtained from electrophoresis in polyarcylamide gels containing sodium dodecyl sulfate and from sedimentation equilibrium analysis of the protein dissolved in 6 M guanidine hydrochloride. The molecular weight of the native enzyme was determined to be 102,000 +/- 2,000 by sedimentation velocity and sedimentation equilibrium analysis. Aspartate transcarbamylase thus appears to be a trimeric protein; cross-linking with dimethyl suberimidate and electrophoretic analysis confirmed this structure. B. subtilis aspartate transcarbamylase has an amino acid composition quite similar to that of the catalytic subunit from Escherichia coli aspartate transcarbamylase; only the content of four amino acids is substantially different. The denaturated enzyme has one free sulfhydryl group. Aspartate transcarbamylase exhibited Michaelis-Menten kinetics and was neither inhibited nor activated by nucleotides. Several anions stimulated activity 2- to 5-fold. Immunochemical studies indicated very little similarity between B. subtilis and E. coli aspartate transcarbamylase or E. coli aspartate transcarbamylase catalytic subunit.     

Purification and some properties of an extracellular maltase from Bacillus subtilis.

Bacillus subtilis P-11, capable of producing extracellular maltase, was isolated from soil. Maximum enzyme production was obtained on a medium containing 2.0% methyl-alpha-D-glucose, 0.5% phytone, and 0.2% yeast extract. After the removal of cells, extracellular maltase was precipitated by ammonium sulfate (85% saturation). The enzyme was purified by using the following procedures: Sephadex G-200 column chromatography, diethylaminoethyl-Sephadex A-50 ion-exchange column chromatography, and a second Sephadex G-200 column chromatography. A highly purified maltase without amylase or proteinase activities was obtained. Some properties of the extracellular maltase were determined: optimum pH, 6.0; optimum temperature, 45 C, when the incubation time was 30 min; pH stability, within 5.5 to 6.5; heat stability, stable up to 45 C; isoelectric point, pH 6.0 (by gel-isoelectric focusing); molecular weight, 33,000 (by gel filtration with Sephadex G-200); substrate specificity: the relative rates of hydrolysis of maltose, maltotriose, isomaltose, and maltotetraose were 100:15:14:4, respectively, and there was no activity toward alkyl or aryl-alpha-D-glucosides, amylose, or other higher polymers. Transglucosylase activity was present. Glucose and tris(hydroxymethyl)aminomethane were competitive inhibitors with Ki values of 4.54 and 75.08 mM, respectively; cysteine was a noncompetitive inhibitor. Michaelis constants were 5 mM for maltose, 1 mM for maltoriose, and 10 mM for isomaltose. A plot of pKm (-log Km) versus pH revealed two deflection points, one each at 5.5 and 6.5; these probably corresponded to an imidazole group of a histidine residue in or near the active center; this assumption was supported by the strong inhibition of enzyme activity by rose bengal.     

Purification and some properties of an extracellular maltase from Bacillus subtilis.

Bacillus subtilis P-11, capable of producing extracellular maltase, was isolated from soil. Maximum enzyme production was obtained on a medium containing 2.0% methyl-alpha-D-glucose, 0.5% phytone, and 0.2% yeast extract. After the removal of cells, extracellular maltase was precipitated by ammonium sulfate (85% saturation). The enzyme was purified by using the following procedures: Sephadex G-200 column chromatography, diethylaminoethyl-Sephadex A-50 ion-exchange column chromatography, and a second Sephadex G-200 column chromatography. A highly purified maltase without amylase or proteinase activities was obtained. Some properties of the extracellular maltase were determined: optimum pH, 6.0; optimum temperature, 45 C, when the incubation time was 30 min; pH stability, within 5.5 to 6.5; heat stability, stable up to 45 C; isoelectric point, pH 6.0 (by gel-isoelectric focusing); molecular weight, 33,000 (by gel filtration with Sephadex G-200); substrate specificity: the relative rates of hydrolysis of maltose, maltotriose, isomaltose, and maltotetraose were 100:15:14:4, respectively, and there was no activity toward alkyl or aryl-alpha-D-glucosides, amylose, or other higher polymers. Transglucosylase activity was present. Glucose and tris(hydroxymethyl)aminomethane were competitive inhibitors with Ki values of 4.54 and 75.08 mM, respectively; cysteine was a noncompetitive inhibitor. Michaelis constants were 5 mM for maltose, 1 mM for maltoriose, and 10 mM for isomaltose. A plot of pKm (-log Km) versus pH revealed two deflection points, one each at 5.5 and 6.5; these probably corresponded to an imidazole group of a histidine residue in or near the active center; this assumption was supported by the strong inhibition of enzyme activity by rose bengal.     

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.     

Purification and properties of glucose-6-phosphate dehydrogenase from Bacillus subtilis spores.

Glucose-6-phosphate dehydrogenase [D-glucose-6-phosphate: NADP oxidoreductase, EC. 1. 1. 1. 49] obtained from spores of Bacillus subtilis PCI 219 strain was partially purified by filtration on Sephadex G-200, ammonium sulfate fractionation and chromatography on DEAE-Sephadex A-25 (about 54-fold). The optimum pH for stability of this enzyme was about 6.3 and the optimum pH for the reaction about 8.3. The apparent Km values of the enzyme were 5.7 X 10(-4) M for glucose-6-phosphate and 2.4 X 10(-4) M for nicotinamide adenine dinucleotide phosphate (NADP). The isoelectric point was about pH 3.9. The enzyme activity was unaffected by the addition of Mg++ or Ca++. The inactive glucose-6-phosphate dehydrogenase obtained from the spores heated at 85 C for 30 min was not reactivated by the addition of ethylenediaminetetraacetic acid, dipicolinic acid or some salts unlike inactive glucose dehydrogenase.     

Purification and properties of two membrane alkaline phosphatases from Bacillus subtilis 168.

Two alkaline phosphatases were extracted from the membranes of Bacillus subtilis 168 stationary-phase cells and purified as homogeneous proteins by hydroxyapatite column chromatography. Alkaline phosphatases I and II differed in several properties such as subunit molecular weight, substrate specificity, thermostability, Km, pH stability, and peptide maps.     

Glutamate dehydrogenase from Bacillus subtilis PCI 219. I. Purification and properties.

Bacillus subtilis PCI 219 has a single glutamate dehydrogenase (GDH) [EC 1.4.1.3] with dual coenzyme specificity [for NAD(H) and NADP(H)]. The enzyme was purified 800-fold from crude extracts of B. subtilis from the post-exponential phase of growth and showed one significant protein band on gel electrophoresis. This band was determined, by activity staining, to have all the GDH nucleotide specificities. Its molecular weight was estimated to be 250,000+/-20,000 by gel filtration, and 270,000+/-30,000 by zone centrifugation in a sucrose density gradient. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate showed that GDH has a subunit size of about 57,000. The pI of GDH was found to bepH 3.7 by isoelectric focusing. GDH exhibited nonlinear kinetics in the reduction of NAD+, and in the reverse direction, the substrate, NH4+, was strongly inhibitory at high concentrations. Purine nucleotides did not affect the activity. The oxidative demination of glutamate was significantly inhibited by the metabolites oxaloacetate and citrate, which acted as allosteric effectors of this enzyme,inhibiting the reaction in one direction. The pH optimum of each of the activities of GDH and the stability of GDH are also reported.     

Purification and some properties of alpha-L-arabinofuranosidase from Bacillus subtilis 3-6.

alpha-L-Arabinofuranosidase (EC 3.2.1.55) was purified from culture supernatant of Bacillus subtilis 3-6. The enzyme had a molecular weight of 61,000 and displayed maximum activity at pH 7.0 and 60 degrees C. It released arabinose from O-alpha-L-arabinofuranosyl-(1-->3)-O-beta-D-xylopyranosyl-(1-->4)-D-x ylopyranos e (A1X2), O-beta-D-xylopyranosyl-(1-->4)-[O-alpha-L-arabinofuranosyl-(1-->3)]- O-beta-D-xylopyranosyl-(1-->4)-D-xylopyranose (A1X3), and arabinan, but not from O-beta-D-xylopyranosyl-(1-->2)-O-alpha-L- arabinofuranosyl-(1-->3)-O-beta-D-xylopyranosyl-(1-->4)-O-beta-D-xylopyr anosyl- (1-->4)-D-xylopyranose (A1X4), arabinoxylan, gum arabic, or arabinogalactan.     

Purification and properties of an intracellular calmodulinlike protein from Bacillus subtilis cells.

Although calcium ions are crucial in a variety of bacterial processes, including spore development, reports of calmodulin in procaryotes have been few. We have purified to homogeneity a calmodulinlike protein (CaLP) from sporulating cells of Bacillus subtilis grown in a chemically defined sporulation medium; purification involved heat treatment, fractionation with ammonium sulfate, affinity chromatography, and gel filtration on high-performance columns. The protein was eluted from a phenothiazine affinity column in a calcium ion-dependent manner, stained poorly with Coomassie blue and silver stain dyes, bound poorly to nitrocellulose filters, and was not an inhibitor of the major intracellular serine proteinase. It stimulated bovine brain phosphodiesterase in a dose- and Ca2(+)-dependent manner and stimulated NAD kinase from peas in a dose-dependent manner. The B. subtilis calmodulin reacted with anti-bovine brain calmodulin antibodies in enzyme-linked immunoabsorbance assays. The amino acid composition data showed it to be distinctly different from eucaryotic calmodulins, having particularly high levels of serine and glycine. The pI of the protein was estimated to be 4.9 to 5.0. The molecular weight was estimated to be 23,000 or 25,000, based on amino acid composition and detergent gel electrophoresis, respectively. The protein reacted with rhodamine isothiocyanate, which blocked its enzyme-activating capacity and greatly increased its electrophoretic mobility and Coomassie dye-binding ability.     

Purification of Prephenate dehydratase from Bacillus subtilis.

Prephenate dehydratase has been purified 10,000-fold from the crude extracts of Bacillus subtilis. The procedure takes advantage of the dissociation of the enzyme to a 55,000-dalton form in the presence of the negative effector, phenylalanine, and its association to a 210,000-dalton form in the presence of the positive effector, methionine. These two forms of the enzyme were separated from the bulk of the other proteins present in the crude extracts by gel filtration alternately in the presence of the two effectors. Sodium dodecyl sulfate electrophoretic analysis showed the enzyme is composed of apparently identical 28,000-dalton polypeptides.