Purification and Characterization of Gentisate 1,2-Dioxygenases from Pseudomonas alcaligenes NCIB 9867 and Pseudomonas putida NCIB 9869

1999 ◽  
Vol 65 (3) ◽  
pp. 946-950 ◽  
Author(s):  
Yongmei Feng ◽  
Hoon Eng Khoo ◽  
Chit Laa Poh

ABSTRACT Two 3-hydroxybenzoate-inducible gentisate 1,2-dioxygenases were purified to homogeneity from Pseudomonas alcaligenes NCIB 9867 (P25X) and Pseudomonas putida NCIB 9869 (P35X), respectively. The estimated molecular mass of the purified P25X gentisate 1,2-dioxygenase was 154 kDa, with a subunit mass of 39 kDa. Its structure is deduced to be a tetramer. The pI of this enzyme was established to be 4.8 to 5.0. The subunit mass of P35X gentisate 1,2-dioxygenase was 41 kDa, and this enzyme was deduced to exist as a dimer, with a native molecular mass of about 82 kDa. The pI of P35X gentisate 1,2-dioxygenase was around 4.6 to 4.8. Both of the gentisate 1,2-dioxygenases exhibited typical saturation kinetics and had apparent Km s of 92 and 143 μM for gentisate, respectively. Broad substrate specificities were exhibited towards alkyl and halogenated gentisate analogs. Both enzymes had similar kinetic turnover characteristics for gentisate, with k cat/Km values of 44.08 × 104 s−1 M−1 for the P25X enzyme and 39.34 × 104 s−1M−1 for the P35X enzyme. Higherk cat/Km values were expressed by both enzymes against the substituted gentisates. Significant differences were observed between the N-terminal sequences of the first 23 amino acid residues of the P25X and P35X gentisate 1,2-dioxygenases. The P25X gentisate 1,2-dioxygenase was stable between pH 5.0 and 7.5, with the optimal pH around 8.0. The P35X enzyme showed a pH stability range between 7.0 and 9.0, and the optimum pH was also 8.0. The optimal temperature for both P25X and P35X gentisate 1,2-dioxygenases was around 50°C, but the P35X enzyme was more heat stable than that from P25X. Both enzymes were strongly stimulated by 0.1 mM Fe2+ but were completely inhibited by the presence of 5 mM Cu2+. Partial inhibition of both enzymes was also observed with 5 mM Mn2+, Zn2+, and EDTA.

2005 ◽  
Vol 187 (22) ◽  
pp. 7696-7702 ◽  
Author(s):  
Xiaoli Gao ◽  
Chew Ling Tan ◽  
Chew Chieng Yeo ◽  
Chit Laa Poh

ABSTRACT The xlnD gene from Pseudomonas alcaligenes NCIMB 9867 (strain P25X) was shown to encode 3-hydroxybenzoate 6-hydroxylase I, the enzyme that catalyzes the NADH-dependent conversion of 3-hydroxybenzoate to gentisate. Active recombinant XlnD was purified as a hexahistidine fusion protein from Escherichia coli, had an estimated molecular mass of 130 kDa, and is probably a trimeric protein with a subunit mass of 43 kDa. This is in contrast to the monomeric nature of the few 3-hydroxybenzoate 6-hydroxylases that have been characterized thus far. Like other 3-hydroxybenzoate 6-hydroxylases, XlnD could utilize either NADH or NADPH as the electron donor. P25X harbors a second 3-hydroxybenzoate 6-hydroxylase II that was strictly inducible by specific aromatic substrates. However, the degradation of 2,5-xylenol and 3,5-xylenol in strain P25X was found to be dependent on the xlnD-encoded 6-hydroxylase I and not the second, strictly inducible 6-hydroxylase II.


1991 ◽  
Vol 279 (3) ◽  
pp. 675-682 ◽  
Author(s):  
B C Lockwood ◽  
G H Coombs

Methionine gamma-lyase (EC 4.4.1.11) was purified to homogeneity from the anaerobic protozoan parasite Trichomonas vaginalis by a series of f.p.l.c. procedures. The enzyme catalyses alpha gamma- and alpha beta-elimination reactions of a number of derivatives of methionine and cysteine. It also catalyses gamma-replacement reactions of the thiomethyl group of methionine, homocysteine and ethionine to yield the corresponding S-substituted homocysteine derivative. The enzyme is pyridoxal 5′-phosphate-dependent, has a native molecular mass of approx. 160 kDa and consists of four apparently identical subunits of molecular mass 43-45 kDa. The absorption spectrum of the enzyme is typical of those obtained for other pyridoxal 5′-phosphate-dependent enzymes, and the holoenzyme can be resolved to the apoenzyme by incubation with hydroxylamine and reconstituted by addition of the cofactor. The enzyme activity is significantly affected by carbonyl and thiol reagents, is competitively inhibited by a number of substrate analogues and is completely inactivated by the suicide inhibitor DL-propargylglycine. The T. vaginalis enzyme is similar, in terms of activity and properties, to the enzymes found in a number of species of bacteria that metabolize methionine under anaerobic conditions. It is suggested that methionine catabolism may be of particular importance to the survival of T. vaginalis under microaerophilic conditions in its host.


1994 ◽  
Vol 300 (2) ◽  
pp. 557-565 ◽  
Author(s):  
C Alban ◽  
P Baldet ◽  
R Douce

Young pea leaves contain two structurally different forms of acetyl-CoA carboxylase (EC 6.4.1.2; ACCase). A minor form, which accounted for about 20% of the total ACCase activity in the whole leaf, was detected in the epidermal tissue. This enzyme was soluble and was purified to homogeneity from young pea leaf extracts. It consisted of a dimer of two identical biotinyl subunits of molecular mass 220 kDa. In this respect, this multifunctional enzyme was comparable with that described in other plants and in other eukaryotes. A predominant form was present in both the epidermal and mesophyll tissues. In mesophyll protoplasts, ACCase was detected exclusively in the soluble phase of chloroplasts. This enzyme was partially purified from pea chloroplasts and consisted of a freely dissociating complex, the activity of which may be restored by combination of its separated constituents. The partially purified enzyme was composed of several subunits of molecular masses ranging from 32 to 79 kDa, for a native molecular mass > 600 kDa. One of these subunits, of molecular mass 38 kDa, was biotinylated. This complex subunit structure was comparable with that of microorganisms and was referred to as a ‘prokaryotic’ form of ACCase. Biochemical parameters were determined for both ACCase forms. Finally, both pea leaf ACCases exhibited different sensitivities towards the grass ACCase herbicide, diclofop. This compound had no effect on the ‘prokaryotic’ form of ACCase, while the ‘eukaryotic’ form was strongly inhibited.


1992 ◽  
Vol 285 (2) ◽  
pp. 661-666 ◽  
Author(s):  
M C Silvestrini ◽  
F Cutruzzolà ◽  
R D'Alessandro ◽  
M Brunori ◽  
N Fochesato ◽  
...  

Nitrite reductase from Pseudomonas aeruginosa has been successfully expressed in Pseudomonas putida. The purified recombinant enzyme contains haem c but no haem d1. Nonetheless, like the holoenzyme from Ps. aeruginosa, it is a stable dimer (molecular mass 120 kDa), and electron transfer to oxidized azurin is biphasic and follows bimolecular kinetics (k1 = 1.5 x 10(5) and k2 = 2.2 x 10(4) M-1.s-1). Unlike the chemically produced apoenzyme, recombinant nitrite reductase containing only haem c is water-soluble, stable at neutral pH and can be quantitatively reconstituted with haem d1, yielding a holoenzyme with the same properties as that expressed by Ps. aeruginosa (namely optical and c.d. spectra, molecular mass, cytochrome c551 oxidase activity and CO-binding kinetics).


1999 ◽  
Vol 43 (7) ◽  
pp. 1578-1583 ◽  
Author(s):  
Hitoshi Komatsuzawa ◽  
Gil H. Choi ◽  
Kouji Ohta ◽  
Motoyuki Sugai ◽  
Monique T. Tran ◽  
...  

ABSTRACT A previously unrecognized penicillin binding protein (PBP) gene,pbpF, was identified in Staphylococcus aureus. This gene encodes a protein of 691 amino acid residues with an estimated molecular mass of 78 kDa. The molecular mass is very close to that of S. aureus PBP2 (81 kDa), and the protein is tentatively named PBP2B. PBP2B has three motifs, SSVK, SSN, and KTG, that can be found in PBPs and β-lactamases. Recombinant PBP2B (rPBP2B), which lacks a putative signal peptide at the N terminus and has a histidine tag at the C terminus, was expressed inEscherichia coli. The purified rPBP2B was shown to have penicillin binding activity. A protein band was detected from S. aureus membrane fraction by immunoblotting with anti-rPBP2B serum. Also, penicillin binding activity of the protein immunoprecipitated with anti-rPBP2B serum was detected. These results suggest the presence of PBP2B in S. aureus cell membrane that covalently binds penicillin. The internal region ofpbpF and PBP2B protein were found in all 12 S. aureus strains tested by PCR and immunoblotting.


1993 ◽  
Vol 293 (1) ◽  
pp. 283-288 ◽  
Author(s):  
L J Klimczak ◽  
A R Cashmore

Casein kinase I from broccoli was purified approximately 65,000-fold by chromatography on phosphocellulose, phenyl-Sepharose, CM-Sephacel, and affinity chromatography on N-(2-aminoethyl)-5-chloroisoquinolone-8-sulphonamide (CKI-7)-Sepharose. The catalytic subunit of casein kinase I was identified as a 36-38 kDa polypeptide doublet by using the technique of activity gel assay after SDS/PAGE with casein as a gel-incorporated substrate. A silver-stained polypeptide doublet of the same molecular mass constituted at least 95% of the protein in the final preparation, corresponding to a specific activity of approximately 1800 nmol/min per mg of protein. The enzyme was found to be a monomer by gel filtration and glycerol gradient sedimentation; the native molecular mass was calculated to be 34.2 kDa. These characteristics, as well as other essential features of plant casein kinase I activity, such as substrate specificity and sensitivity to inhibitors, were found to be similar to those established for animal casein kinase I. Broccoli casein kinase I showed weak immunological cross-reactivity with antibodies raised against bovine casein kinase I.


1998 ◽  
Vol 180 (2) ◽  
pp. 296-302 ◽  
Author(s):  
Stefan R. Kaschabek ◽  
Thomas Kasberg ◽  
Dagmar Müller ◽  
Astrid E. Mars ◽  
Dick B. Janssen ◽  
...  

ABSTRACT A purification procedure for a new kind of extradiol dioxygenase, termed chlorocatechol 2,3-dioxygenase, that converts 3-chlorocatechol productively was developed. Structural and kinetic properties of the enzyme, which is part of the degradative pathway used for growth ofPseudomonas putida GJ31 with chlorobenzene, were investigated. The enzyme has a subunit molecular mass of 33.4 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Estimation of the native M r value under nondenaturating conditions by gel filtration gave a molecular mass of 135 ± 10 kDa, indicating a homotetrameric enzyme structure (4 × 33.4 kDa). The pI of the enzyme was estimated to be 7.1 ± 0.1. The N-terminal amino acid sequence (43 residues) of the enzyme was determined and exhibits 70 to 42% identity with other extradiol dioxygenases. Fe(II) seems to be a cofactor of the enzyme, as it is for other catechol 2,3-dioxygenases. In contrast to other extradiol dioxygenases, the enzyme exhibited great sensitivity to temperatures above 40°C. The reactivity of this enzyme toward various substituted catechols, especially 3-chlorocatechol, was different from that observed for other catechol 2,3-dioxygenases. Stoichiometric displacement of chloride occurred from 3-chlorocatechol, leading to the production of 2-hydroxymuconate.


Microbiology ◽  
2009 ◽  
Vol 155 (9) ◽  
pp. 3083-3091 ◽  
Author(s):  
Jaigeeth Deveryshetty ◽  
Prashant S. Phale

Pseudomonas sp. strain PPD can metabolize phenanthrene as the sole source of carbon and energy via the ‘phthalic acid’ route. The key enzyme, 1-hydroxy-2-naphthoic acid dioxygenase (1-HNDO, EC 1.13.11.38), was purified to homogeneity using a 3-hydroxy-2-naphthoic acid (3-H2NA)-affinity matrix. The enzyme was a homotetramer with a native molecular mass of 160 kDa and subunit molecular mass of ∼39 kDa. It required Fe(II) as the cofactor and was specific for 1-hydroxy-2-naphthoic acid (1-H2NA), with K m 13.5 μM and V max 114 μmol min−1 mg−1. 1-HNDO failed to show activity with gentisic acid, salicylic acid and other hydroxynaphthoic acids tested. Interestingly, the enzyme showed substrate inhibition with a K i of 116 μM. 1-HNDO was found to be competitively inhibited by 3-H2NA with a K i of 24 μM. Based on the pH-dependent spectral changes, the enzyme reaction product was identified as 2-carboxybenzalpyruvic acid. Under anaerobic conditions, the enzyme failed to convert 1-H2NA to 2-carboxybenzalpyruvic acid. Stoichiometric studies showed the incorporation of 1 mol O2 into the substrate to yield 1 mol product. These results suggest that 1-HNDO from Pseudomonas sp. strain PPD is an extradiol-type ring-cleaving dioxygenase.


1994 ◽  
Vol 304 (1) ◽  
pp. 195-200 ◽  
Author(s):  
P P Van Veldhoven ◽  
P Van Rompuy ◽  
J C T Vanhooren ◽  
G P Mannaerts

The acyl-CoA oxidase, catalysing the peroxisomal desaturation of the CoA-ester of trihydroxycoprostanic acid, a bile acid intermediate, has been purified to homogeneity from rat liver. Its native molecular mass, as determined by gel filtration and native gel electrophoresis, was 120 and 175 kDa respectively, suggesting a homodimeric protein consisting of 68.6 kDa subunits. If isolated in the presence of FAD, the enzyme showed a typical flavoprotein spectrum and contained most likely 2 mol of FAD per mol of enzyme. The cofactor, however, was loosely bound. The enzyme acted exclusively on 2-methyl-branched compounds, including pristanoyl-CoA and 2-methylhexanoyl-CoA if albumin was present. Important parameters to obtain a pure and active enzyme were the following: (1) using chromatographic separations like hydrophobic interaction and metal affinity, which allow the presence of high salt concentrations, conditions which stabilize the oxidase; (2) avoiding dialysis and (NH4)2SO4 precipitation; (3) including, when appropriate, FAD, dithiothreitol and a diol-compound in the solvents; and (4) carefully monitoring the removal of other acyl-CoA oxidases which possess the same native molecular mass and subunit size.


1989 ◽  
Vol 261 (3) ◽  
pp. 993-998 ◽  
Author(s):  
H Sobek ◽  
H Görisch

The carboxylesterase (serine esterase, EC 3.1.1.1) from Sulfolobus acidocaldarius was purified 940-fold to homogeneity by an improved purification procedure with a yield of 57%. In the presence of alcohols the enzyme catalyses the transfer of the substrate acyl group to alcohols in parallel to hydrolysis. The results show the existence of an alcohol-binding site and a competitive partitioning of the acyl-enzyme intermediate between water and alcohols. Aniline acts also as a nucleophilic acceptor for the acyl group. On the basis of titration with diethyl p-nitrophenyl phosphate, a number of four active centres is determined for the tetrameric carboxylesterase. The sequence of 20 amino acid residues at the esterase N-terminus and the amino acid composition are reported.


Sign in / Sign up

Export Citation Format

Share Document