kappa-Carrageenase from Pseudomonas carrageenovora.

A kappa-carrageenase was isolated from the cell-free medium of cultured Pseudomonas carrageenovora. From dodecylsulphate/polyacrylamide gel electrophoresis, a single protein (identified as the kappa-carrageenase) was detected in the medium. Activity against nominal carrageenan types and inspection of the products indicate the enzyme to be a kappa-carrageenase. Purification is described here by ammonium sulphate precipitation and subsequent CM-Sepharose CL-6B ion-exchange chromatography. Molecular weight was estimated as 35,000 by dodecylsulphate/polyacrylamide gel electrophoresis. Products of degradation were analysed by gel filtration, spectrophotometric assays and 13C nuclear magnetic resonance. These results are consistent with the product of limit digest being neocarrabiose 4-O-sulphate.     

Formaldehyde dehydrogenase from Pseudomonas putida. Purification and some properties

Formaldehyde dehydrogenase was isolated and purified in an overall yield of 12% from cell-free extract of Pseudomonas putida C-83 by chromatographies on columns of DEAE-cellulose, DEAE-Sephadex A-50, and hydroxyapatite. The purified enzyme was homogeneous as judged by disc gel electrophoresis and was most active at pH 7.8 using formaldehyde as a substrate. The enzyme was also active toward acetaldehyde, propionaldehyde, glyoxal, and pyruvaldehyde, though the reaction rates were low. The enzyme was NAD+-linked but did not require the external addition of glutathione, in contrast with the usual formaldehyde dehydrogenase from liver mitochondria, baker's yeast, and some bacteria. The enzyme was markedly inhibited by Ni2+, Pd2+, Hg2+, p-chloromercuribenzoate, and phenylmethanesulfonyl fluoride. The molecular weight of the enzyme was estimated to be 150,000 by the gel filtration method, and analysis by SDS-polyacrylamide gel electrophoresis indicated that the enzyme was composed of two subunit monomers. Kinetic analysis gave Km values of 67 microM for formaldehyde and 56 microM for NAD+, and suggested that the reaction proceeds by a "Ping-pong" mechanism. The enzyme catalyzed the oxidation of formaldehyde accompanied by the stoichiometric reduction of NAD+, but no reverse reaction was observed.     

Purification and some properties of cyclohexylamine oxidase from a Pseudomonas sp.

Cyclohexylamine oxidase was purified 90-fold from cell-free extracts of Pseudomonas sp. capable of assimilating sodium cyclamate. The purified enzyme was homogeneous in disc electrophoresis, and the molecular weight was found to be approximately 80,000 by gel filtration. The enzyme catalyzed the following reaction: cyclohexylamine+O2+H2O leads to cyclohexanone+NH3+H2O2. The enzyme thus can be classified as an amine oxidase; it utilized oxygen as the ultimate electron acceptor. The pH optimum of the reaction was 6.8 and the apparent Km value for cyclohexylamine was 2.5 X 10(-4) M. The enzyme was highly specific for the deamination of alicyclic primary amines such as cyclohexylamine, but was found to be inactive toward ordinary amines used as substrates for amine oxidases. The enzyme solution was yellow in color and showed a typical flavoprotein spectrum; the addition of cyclohexylamine under anaerobic conditions caused reduction of the flavin in the native enzyme. The flavin of the prosthetic group was identified as FAD by thin layer chromatography. The participation of sulfhydryl groups in the enzymic action was also suggested by the observation that the enzyme activity was inhibited in the presence of PCMB and could be recovered by the addition of glutathione.     

Purification and some properties of intracellular esterase from Pseudomonas fluorescens

A novel esterase was found in Pseudomonas fluorescens cells and purified to homogeneity as determined by polyacrylamide gel electrophoresis. The esterase was extracted from the cells by freeze-thawing and hypotonic treatment. Purification was achieved by ammonium sulfate precipitation, followed by successive chromatographies on DEAE-cellulose and benzylamine-agarose and then electrophoresis. The enzyme catalyzed the hydrolysis of methyl esters, such as methyl butyrate, but its hydrolyzing activity decreased with increase in the chain length of the alcohol moiety, and it did not catalyze the hydrolysis of triacylglycerols, such as triacetin. In contrast, the enzyme acted on various acyl residues in a series of methyl esters, such as dimethyl succinate, methyl methacrylate, and dimethyl malate. The optimum pH for activity of this enzyme with methyl butyrate was 7.0-8.5. The enzyme was inhibited by phenylmethylsulfonylfluoride. Its molecular weight was estimated as 48,000 by molecular sieve electrophoresis and gel filtration on Sephadex G-150.     

Purification and some properties of the citrate synthase from a marine Pseudomonas.

Citrate synthase (citrate-oxaloacetate lyase (CoA acetylating), EC 4.1.3.7) has been purified to electrophoretic homogeneity from a marine Pseudomonas. The enzyme was made up of identical subunits, with a molecular wieght of about 53 000, as determined by sodium dodecyl sulphate - polyacrylamide gel electrophoresis. The native enzyme (citrate synthase II, CS II) could be dissociated by dialysis against 20 mM phosphate (Pi), pH 7; the enzyme thus obtained (citrate synthase I, CS I) was still active, but presented different molecular weight and kinetic and regulatory properties. CS II was activated by adenosine monophosphate (AMP), Pi, and KCl, and inhibited by reduced nicotinamide adenine dinucleotide (NADH), being apparently insensitive to adenosine triphosphate (ATP) and adenosine diphosphate (ADP). The inhibition by NADH was completely counteracted by 0.1 mM AMP, but not by 50 mM Pi or 0.1 M KCl. The activation by KCl and Pi, or by KCl and AMP was nearly additive, whereas that by AMP and Pi was not. The activators acted essentially by increasing Vmax, although they also caused a decrease in the Km values. CS I was inhibited by ATP, ADP, AMP, and KCl, and was insensitive to NADH. CS I could be reassociated after elimination of Pi by dialysis, regaining the higher molecular weight and the activation by AMP characteristic of CS II.     

Purification and some properties of carbon monoxide dehydrogenase from Pseudomonas carboxydohydrogena

A soluble yellow CO dehydrogenase from CO-autotrophically grown cells of Pseudomonas carboxydohydrogena was purified 35-fold in seven steps to better than 95% homogeneity with a yield of 30%. The final specific activity was 180 μmol of acceptor reduced per min per mg of protein as determined by an assay based on the CO-dependent reduction of thionin. Methyl viologen, nicotinamide adenine dinucleotide (phosphate), flavin mononucleotide, and flavin adenine dinucleotide were not reduced by the enzyme, but methylene blue, thionin, and toluylene blue were reduced. The molecular weight of native enzyme was determined to be 4 × 10⁵. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate revealed at least three nonidentical subunits of molecular weights 14,000 (α), 28,000 (β), and 85,000 (γ). The ratio of densities of each subunit after electrophoresis was about 1:2:6 (α/β/γ), suggesting an α₃β₃γ₃ structure for the enzyme. The purified enzyme was free of formate dehydrogenase and nicotinamide adenine dinucleotide-specific hydrogenase activities, but contained particulate hydrogenase-like activity with thionin as electron acceptor. Known metalchelating agents tested had no effect on CO dehydrogenase activity. No divalent cations tested stimulated enzyme activity. The native enzyme does not contain Ni since cells assimilated little ⁶³Ni during growth, and the specific ⁶³Ni content of the enzyme declined during purification. The isoelectric point of the native enzyme was found to be 4.5 to 4.7. The K_m for CO was found to be 63 μM. The spectrum of the enzyme and its protein-free extract revealed that it contains bound flavin. The cofactor was flavin adenine dinucleotide based on enzyme digestion and thin-layer chromatography. One mole of native enzyme contains at least 3 mol of noncovalently bound flavin adenine dinucleotide.     

Purification and some properties of Pseudomonas fluorescens lipase

Lipase (triacylglycerol lipase, EC 3.1.1.3) has been purified from Pseudomonas fluorescens wild strain by chromatography on DEAE-cellulose and octyl-Sepharose CL-4B. The yield was 21% and the specific activity of the purified enzyme 4780 U/mg protein. It showed a Mr of about 45 x 10(4) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme is active over a wide pH range and at 50-55 degrees C.     

Purification, crystallization, and some properties of creatine amidinohydrolase from Pseudomonas putida.

A method was developed for purification and crystallization of creatinase [creatine amidinohydrolase, EC 3.5.3.3] from Pseudomonas putida var. naraensis C-83. The purified preparation appeared homogeneous on disc electrophoresis and ultracentrifugation and had a molecular weight of 94,000. It was most active at pH 8 and stable between pH 6 and 8 for 24 hr at 37 degrees. SDS-polyacrylamide gel electrophoresis indicated that the native enzyme was made up of two subunit monomers, the molecular weights of which were estimated to be 47,000. Inhibition experiments suggested that a sulfhydryl group is located in or near the active site of the enzyme.     

Purification and some properties of a soluble benzene-oxidizing system from a strain of Pseudomonas.

1. A soluble enzyme system which oxidizes benzene to cis-1,2-dihydroxycyclohexa-3,5-diene (cis-benzene glycol) was obtained from a species of Pseudomonas grown on benzene as the major carbon source. 2. The system was shown to consist of three protein components. Two of these were non-haem-iron proteins of molecular weight approx. 21,000 and approx. 186,000 and the other was a flavoprotein of molecular weight approx. 60,000. 3. Fe2+ and NADH were essential cofactors for benzene oxidation.     

Purification and some properties of two proteases from Pseudomonas aeruginosa No. 700/75

Two extracellular proteases have been isolated from the culture supernatant of a virulent strain of Pseudomonas aeruginosa. The enzymes were purified in a three-step procedure involving ammonium sulfate fractionation, acetone precipitation and column chromatography on DE-52 cellulose. The specific activity of protease I was 22.2 U/mg of protein and protease II 6.6 U/mg of protein. Immunological properties and electrophoretic mobilities of the two forms were different. The two forms differ in substrate specificity (only from I exhibited elastinolytic activity) and pH optimum (pH 7.5 and pH 10 for form I and II, respectively).     

Purification and properties of pantohenase from Pseudomonas fluorescens.

Pantothenase (EC 3.5.1.22) from Pseudomonas fluorescens UK-1 was purified to homogeneity as judged by disc-gel electrophoresis and isoelectric focusing. The purification procedure consisted of four steps: DEAE-Sephadex chromatography, (NH4)2SO4 precipitation, hydroxyapatite chromatography and preparative polyacrylamide-gel electrophoresis. Gel filtration on Ultrogel AcA 34 was used to determine the molecular weight, and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis to study the subunit molecular weight. The enzyme appeared to be composed of two subunits with mol.wts. of approx. 50000 each. The total mol.wt. of the enzyme was thus about 100000. The isoelectric point was 4.7 at 10 degrees C.     

Purification and properties of L-glutaminase-L-asparaginase from Pseudomonas acidovorans.

An enzyme that catalyzes the hydrolysis of both glutamine and asparagine has been purified to homogeneity from extracts of Pseudomonas acidovorans. The enzyme having a ratio of glutaminase to asparaginase of 1.45:1.0 can be purified by a relatively simple procedure and is stable upon storage. The glutaminase-asparaginase has a relatively high affinity for L-asparagine (Km=1.5 X 10(-5) M) and L-glutamine (Km=2.2 X 10(-5) M) and has a molecular weight of approximately 156,000 the subunit molecular weight being approximately 39,000. Injections of the enzyme produced only slight increases in the survival time of C3H/HE mice carrying the asparagine-requiring 6C2HED Gardner lymphoma and of white Swiss mice carrying the glutamine-requiring Ehrlich lymphoma.     

Studies on phospholipase C from Pseudomonas aureofaciens. I. Purification and some properties of phospholipase C.

Phospholipase C (phosphatidylcholine cholinephosphohydrolase, EC 3.1.4.3) from Pseudomonas aureofaciens was purified 3600-fold from the culture filtrate with a recovery of 1.6%. Purification was performed with the useof (NH4)2SO4 precipitation, Sephadex G-100 gel filtration and by ion-exchange chromatography on DEAE-Sephadex A-50 and CM-Sephadex C-50. The purified enzyme appeared to be homogeneous as revealed by polyacrylamide disc gel electrophoresis at pH 9.3. The molecular weight was estimated to be 35 000 by gel filtration on Sephadex G-75. Under our experimental conditions, phosphatidylethanolamine was more rapidly hydrolysed than phosphatidylcholine. Lyso forms of these two phosphatides were poor substrates. Phosphatidylserine, phosphatidylglycerol, phosphatidylinositol, cardiolipin and sphingomyelin were not hydrolysed. The enzyme activity with phosphatidylcholine as substrate was slightly stimulated by Ca2+, Mg2+, and Mn2+. However, these cations inhibited the activity with phosphatidylethanolamine as substrate. An anionic detergent, sodium deoxycholate, slightly enhanced the activity when phosphatidylcholine and phosphatidylethanolamine were used as substrates. A cationic detergent, cetyltrimethylammonium bromide, inhibited enzyme activity. EDTA and o-henanthroline inhibited the activity of the enzyme to a marked degree.     

Purification and characterization of the recombinant arylsulfatase cloned from Pseudoalteromonas carrageenovora

Arylsulfatase cloned from a marine aerobic Gram-negative bacterium, Pseudoalteromonas carrageenovora, was overexpressed in Escherichia coli with 10 microM IPTG induction. The expressed recombinant arylsulfatase was purified to homogeneity from the harvested cells through osmotic disruption and column chromatography methods, such as DEAE-cellulose anion exchange chromatography and Heparin-Sepharose affinity chromatography. The purified arylsulfatase was kinetically characterized using the synthetic substrate of phenolic ester, p-nitrophenyl sulfate (pNPS). One unit of arylsulfatase catalyzes the liberation of 1.0 micromol p-nitrophenol from pNPS per minute. The purified enzyme has a specific activity of 468 U/mg with a purification yield of 27% from the cell lysate, and exhibited an estimated molecular mass of 33 kDa in SDS-PAGE analysis. The precursor polypeptide of 36 kDa was processed by releasing a putative signal peptide, and the mature arylsulfatase of 33.1 kDa with a N-terminal sequence of S-E-T-K-N was trafficked to periplasmic space. The enzyme had optimum reaction conditions for activity at pH 7.0 and at a temperature range of 40-45 degrees C. The apparent K(M) and k(cat) of the enzyme for hydrolysis of pNPS at pH 7.0 and at 45 degrees C were determined to be 1.15 mM and 1000 s-1, respectively. Based on inhibitor studies along with optimal pH values and preferential periplasmic location of the enzyme, we suggest that the recombinant arylsulfatase from P. carrageenovora is probably similar to the Klebsiella sulfatase with serine residue in the active site.     

Uronic acid dehydrogenase from Pseudomonas syringae. Purification and properties.

1. Uronic acid dehydrogenase was purified to homogeneity. After a 338-fold purification a yield of 16% was achieved with a specific activity of 81 mumol NADH formed min-1 mg protein-1. 2. The purity of the enzyme was controlled by disc electrophoresis, sodium dodecylsulfate electrophoresis and ultracentrifugation. 3. A molecular weight of 60 000 was determined by gel chromatography and by ultracentrifugation. 4. The native enzyme is composed of two subunits, their molecular weight being 30 000 as estimated by sodium dodecylsulfate electrophoresis. The subunits as such are inactive. 5. The absorption spectrum with a maximum at 278 nm shows no evidence for a prosthetic group. 6. For catalytic activity no SH groups and no metals seem to be necessary. 7. The Michaelis constants determined with the pure enzyme are for glucuronic acid Km = 0.37 mM, galacturonic acid Km = 54 muM and NAD+ (with glucuronic acid) Km = 80 muM. 8. A weak reverse reaction could be observed with glucaric acid lactones at acidic pH. 9. NADH is competitive with NAD+. The inhibitor constant is Ki = 60 muM. 10. The NAD+ binding site seems to be of lower specificity than the uronic acid binding site.     

Purification and properties of formylglutamate amidohydrolase from Pseudomonas putida.

Formylglutamate amidohydrolase (FGase) catalyzes the terminal reaction in the five-step pathway for histidine utilization in Pseudomonas putida. By this action, N-formyl-L-glutamate (FG) is hydrolyzed to produce L-glutamate plus formate. Urocanate, the first product in the pathway, induced all five enzymes, but FG was able to induce FGase alone, although less efficiently than urocanate did. This induction by FG resulted in the formation of an FGase with electrophoretic mobility identical to that of the FGase induced by urocanate. A 9.6-kilobase-pair HindIII DNA fragment containing the P. putida FGase gene was cloned into the corresponding site on plasmid pBEU1 maintained in Escherichia coli. Insertion of the fragment in either orientation on the vector resulted in expression, but a higher level was noted in one direction, suggesting that the FGase gene can be expressed from either of two vector promoters with different efficiencies or from a single vector promoter in addition to a less efficient Pseudomonas promoter. FGase was purified 1,110-fold from the higher-expression clone in a yield of 10% through six steps. Divalent metal ions stimulated activity, and among those tested (Co, Fe, Zn, Ca, Ni, Cd, Mn, and Mg), Co(II) was the best activator, followed by Fe(II). FGase exhibited a Km of 14 mM for FG and a specific activity of 100 mumol/min per mg of protein in the presence of 5 mM substrate and 0.8 mM CoCl2 at 30 degrees C. The enzyme was maximally active in the range of pH 7 to 8. FGase was found to be a monomer of molecular weight 50,000. N-Acetyl-L-glutamate was not a substrate for the enzyme, but both it and N-formyl-L-aspartate were competitive inhibitors of formylglutamate hydrolysis, exhibiting Ki values of 6 and 9 mM, respectively. The absence of FGase activity as an integral part of histidine breakdown in most other organisms and the somewhat uncoordinated regulation of FGase synthesis with that of the other hut enzymes in Pseudomonas suggest that the gene encoding its synthesis may have evolved separately from the remaining hut genes.