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PubMed2005

Protocatechuate 4,5-dioxygenase from Comamonas testosteroni T-2: biochemical and molecular properties of a new subgroup within class III of extradiol dioxygenases.

Comamonas testosteroni T-2 degraded at least eight aromatic compounds via protocatechuate (PCA), whose extradiol ring cleavage to 2-hydroxy-4-carboxymuconate semialdehyde (HCMS) was catalysed by PCA 4,5-dioxygenase (PmdAB). This inducible, heteromultimeric enzyme was purified. It contained two subunits, alpha (PmdA) and beta (PmdB), and the molecular masses of the denatured proteins were 18 kDa and 31 kDa, respectively. PCA was converted stoichiometrically to HCMS with an apparent K(m) of 55 muM and at a maximum velocity of 1.5 mukat. Structure-activity-relationship analysis by testing 16 related compounds as substrate for purified PmdAB revealed an absolute requirement for the vicinal diol and for the carboxylate group of PCA. Besides PCA, only 5'-hydroxy-PCA (gallate) induced oxygen uptake. The N-terminal amino acid sequence of each subunit was identical to the corresponding sequences in C. testosteroni BR6020, which facilitated sequencing of the pmdAB genes in strain T-2. Small differences in the amino acid sequence had significant effects on enzyme stability. Several homologues of pmdAB were found in sequence databases. Residues involved in substrate binding are highly conserved among the homologues. Their sequences grouped within the class III extradiol dioxygenases. Based on our biochemical and genetic analyses, we propose a new branch of the heteromultimeric enzymes within that class.

Amino Acid Sequence↗

PubMed2006

N-acyl homoserine lactones are degraded via an amidolytic activity in Comamonas sp. strain D1.

Comamonas strain D1 enzymatically inactivates quorum-sensing (QS) signal molecules of the N-acyl homoserine lactone (N-AHSL) family, and exhibits the broadest inactivation range of known bacteria. It degrades N-AHSL with acyl-side chains ranging from 4 to 16 carbons, with or without 3-oxo or 3-hydroxy substitutions. N-AHSL degradation yields HSL but not N-acyl homoserine: strain D1 therefore harbors an amidohydrolase activity. Strain D1 is the fifth bacterium species in which an N-AHSL amidohydrolase is described. Consistent with its N-AHSL degradation ability, strain D1 efficiently quenches various QS-dependent functions in other bacteria, such as violacein production by Chromobacterium violaceum and pathogenicity and antibiotic production in Pectobacterium.

4-Butyrolactone↗

PubMed2005

Metabolism of dibenzofuran and dibenzo-p-dioxin by the biphenyl dioxygenase of Burkholderia xenovorans LB400 and Comamonas testosteroni B-356.

We examined the metabolism of dibenzofuran (DF) and dibenzo-p-dioxin (DD) by the biphenyl dioxygenase (BPDO) of Comamonas testosteroni B-356 and compared it with that of Burkholderia xenovorans LB400. Data showed that both enzymes oxygenated DF at a low rate, but Escherichia coli cells expressing LB400 BPDO degraded DF at higher rate (30 nmol in 18 h) compared with cells expressing B-356 BPDO (2 nmol in 18 h). Furthermore, both BPDOs produced dihydro-dihydroxy-dibenzofuran as a major metabolite, which resulted from the lateral oxygenation of DF. 2,2',3-Trihydroxybiphenyl (resulting from angular oxygenation of DF) was a minor metabolite produced by both enzymes. Deuterated DF was used to demonstrate the production of 2,2',3-dihydroxybiphenyl through angular oxygenation of DF. When tested for their ability to oxygenate DD, both enzymes produced as sole metabolite, 2,2',3-trihydroxybiphenyl ether at about the same rate, indicating similar catalytic properties toward this substrate. Altogether, although LB400 and B-356 BPDOs oxygenate a different range of chlorobiphenyls, their metabolite profiles toward DF and DD are similar. This suggests that co-planarity influences the regiospecificity of BPDO toward DF and DD to a higher extent than the presence of an ortho substituent on the molecule.

Benzofurans↗

PubMed2005

Over-expression in Escherichia coli of a thermally stable and regio-selective nitrile hydratase from Comamonas testosteroni 5-MGAM-4D.

The genes encoding a thermally stable and regio-selective nitrile hydratase (NHase) and an amidase from Comamonas testosteroni 5-MGAM-4D have been cloned and sequenced, and active NHase has been over-produced in Escherichia coli. Maximal activity requires co-expression of a small open reading frame immediately downstream from the NHase beta subunit gene. Compared to the native organism, the E. coli biocatalyst has nearly threefold more NHase activity on a dry cell weight basis, and this activity is significantly more thermally stable. In addition, this biocatalyst converts a wide spectrum of nitrile substrates to the corresponding amides. Such versatility and robustness are desirable attributes of a biocatalyst intended for use in commercial applications.

Amidohydrolases↗

PubMed2005

Impact of membrane fatty acid composition on the uncoupling sensitivity of the energy conservation of Comamonas testosteroni ATCC 17454.

The fatty acid composition of pyruvate-grown Comamonas testosteroni ATCC 17454 was analyzed after growth at 30 and 20 degrees C and after half-maximum growth inhibition caused by different membrane-active chemicals at 30 degrees C. Palmitic acid (16:0), palmitoleic acid (16:1 omega7c) and vaccenic acid (18:1 omega7c) were the dominant fatty acids. At 20 degrees C, the proportion of palmitic acid decreased and those of palmitoleic and vaccenic acid increased. Saturation degree was also lowered when half-maximum growth inhibition was caused by 4-chlorosalicylic acid, 2,4-dichlorophenoxyacetic acid and 2,4-dinitrophenol and, to a lesser extent, in the presence of 2,4-dichlorophenol, phenol and ethanol. It appeared that the dissociated forms of the former group of chemicals were preferentially incorporated near the head group region of the lipid bilayer, thereby somewhat extending the outer region of the membranes, and that the increased amount of bent, unsaturated fatty acids helped to maintain membrane integrity. Irrespective of how the decrease of the saturation degree was triggered, it caused electron transport phosphorylation (adenosine triphosphate synthesis driven by n-hexanol oxidation) to become more sensitive to uncoupling. Apparently, the viscosity and phase stability of the cytoplasmic membrane of C. testosteroni were maintained at the price of a reduced protection against energy toxicity.

Cell Membrane↗

PubMed1999

Characterization of a high-affinity phenol hydroxylase from Comamonas testosteroni R5 by gene cloning, and expression in Pseudomonas aeruginosa PAO1c.

Comamonas testosteroni strain R5 is a phenol-degrading bacterium which expresses a phenol-oxygenating activity that is characterized by low Ks (the apparent half-saturation constant in Haldane's equation) and low K(SI) (the apparent inhibition constant) values. We have now cloned the gene cluster encoding a phenol hydroxylase (phcKLMNOP) and its cognate regulator (phcR) from strain R5. Transformation of Pseudomonas aeruginosa PAO1c (Phenol Catechol+) with pROR502, a derivative of pRO1614 containing the cloned genes, confers the ability to grow on phenol as the sole carbon source. The Ks and K(SI) values for the phenol-oxygenating activity of PAO1c(pROR502) are almost identical to those of strain R5, suggesting that the phcKLMNOP genes encode the major phenol hydroxylase in strain R5. A phylogenetic analysis shows the phenol hydroxylase from strain R5 to be more closely related to toluene/benzene-2-monooxygenase (Tb2m) from Pseudomonas sp. JS150 than to the phenol hydroxylases from P. putida CF600 and BH, or to the phenol hydroxylase from Ralstonia eutropha E2. Analysis of the substrate specificity of PAO1c(pROR502) and PAO1c derivatives expressing phenol hydroxylase from P. putida BH or from R. eutropha E2 indicates that these phenol hydroxylases catalyze the oxidation not only of phenol and cresols but also of toluene and benzene.

Base Sequence↗

PubMed2006

Novel organization of catechol meta pathway genes in the nitrobenzene degrader Comamonas sp. JS765 and its evolutionary implication.

The catechol meta cleavage pathway is one of the central metabolic pathways for the degradation of aromatic compounds. A novel organization of the pathway genes, different from that of classical soil microorganisms, has been observed in Sphingomonas sp HV3 and Pseudomonas sp. DJ77. In a Comamonas sp. JS765, cdoE encoding catechol 2,3-dioxygenase shares a common ancestry only with tdnC of a Pseudomonas putida strain, while codG encoding 2-hydroxymuconic semialdehyde dehydrogenase shows a higher degree of similarity to those genes in classical bacteria. Located between cdoE and cdoG are several putative genes, whose functions are unknown. These genes are not found in meta pathway operons of other microorganisms with the exception of cdoX2, which is similar to cmpX in strain HV3. Therefore, the gene cluster in JS765 reveals a third type of gene organization of the meta pathway.

Amino Acid Sequence↗

PubMed2004

Steroid degradation gene cluster of Comamonas testosteroni consisting of 18 putative genes from meta-cleavage enzyme gene tesB to regulator gene tesR.

Steroid degradation genes of Comamonas testosteroni TA441 are encoded in at least two gene clusters: one containing the meta-cleavage enzyme gene tesB and ORF1, 2, 3; and another consisting of ORF18, 17, tesI, H, A2, and tesA1, D, E, F, G (tesA2 to ORF18 and tesA1 to tesG are encoded in opposite directions). Analysis of transposon mutants with low steroid degradation revealed 13 ORFs and a gene (ORF4, 5, 21, 22, 23, 25, 26, 27, 28, 30, 31, 32, 33, and tesR) involved in steroid degradation in the downstream region of ORF3. TesR, which is almost identical to that of TeiR, a positive regulator of Delta1-dehydrogenase (corresponds to TesH in TA441) and 3alpha-dehydrogenase (currently not identified in TA441), in C. testosteroni ATCC11996 (Pruneda-Paz, 2004), was shown to be necessary for induction of the steroid degradation gene clusters identified in TA441, tesB to tesR, tesA1 to tesG, and tesA2 to ORF18. At least some of the ORFs from ORF3 to ORF33 were suggested to be involved in 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid degradation.

Bacterial Proteins↗

PubMed2005

Biosynthesis of medium chain length poly(3-hydroxyalkanoates) (mcl-PHAs) by Comamonas testosteroni during cultivation on vegetable oils.

Comamonas testosteroni has been studied for its ability to synthesize and accumulate medium chain length poly(3-hydroxyalkanoates) (mcl-PHAs) during cultivation on vegetable oils available in the local market. Castor seed oil, coconut oil, mustard oil, cotton seed oil, groundnut oil, olive oil and sesame oil were supplemented in the mineral medium as a sole source of carbon for growth and PHAs accumulation. The composition of PHAs was analysed by a coupled gas chromatography/mass spectroscopy (GC/MS). PHAs contained C6 to C14 3-hydroxy acids, with a strong presence of 3-hydroxyoctanoate when coconut oil, mustard oil, cotton seed oil and groundnut oil were supplied. 3-hydroxydecanoate was incorporated at higher concentrations when castor seed oil, olive oil and sesame oil were the substrates. Purified PHAs samples were characterized by Fourier Transform Infrared (FTIR) and 13C NMR analysis. During cultivation on various vegetable oils, C. testosteroni accumulated PHAs up to 78.5-87.5% of the cellular dry material (CDM). The efficiency of the culture to convert oil to PHAs ranged from 53.1% to 58.3% for different vegetable oils. Further more, the composition of the PHAs formed was not found to be substrate dependent as PHAs obtained from C. testosteroni during growth on variety of vegetable oils showed similar compositions; 3-hydroxyoctanoic acid and/or 3-hydroxydecanoic acid being always predominant. The polymerizing system of C. testosteroni showed higher preference for C8 and C10 monomers as longer and smaller monomers were incorporated less efficiently.

Comamonas testosteroni↗

PubMedDate not supplied

Comamonas (Pseudomonas) testosteroni endocarditis.

Comamonas testosteroni has rarely been implicated as a human pathogen. We report a case of infectious endocarditis due to this organism, occurring in a 49-year-old man. The posterior leaflet of the mitral valve contained a 1 x 1 cm vegetation and showed myxoid degeneration and acute inflammation. The patient had no evidence of reinfection after 32 months. The infection was almost certainly community acquired, as is usually true for this organism.

Anti-Bacterial Agents↗

PubMed2006

Characterization of MobR, the 3-hydroxybenzoate-responsive transcriptional regulator for the 3-hydroxybenzoate hydroxylase gene of Comamonas testosteroni KH122-3s.

Comamonas testosteroni KH122-3s is an aerobic soil bacterium that utilizes 3-hydroxybenzoate as a sole carbon and energy source. In this strain, 3-hydroxybenzoate hydroxylase (MobA) acts on the initial step of the degradation to produce 3,4-dihydroxybenzoate, which is subsequently subjected to the meta-cleavage pathway leading to tricarboxylic acid cycle intermediates. Gene walking analysis of the upstream region of mobA revealed an open reading frame (mobR) that encodes a transcriptional regulator of the MarR family. Here, we report that MobR negatively regulates the expression of mobA, and that the repression is relieved by binding of 3-hydroxybenzoate, the substrate for MobA. A primer extension experiment was performed to determine the transcription start site for mobA and identified it at 83 bp upstream of the mobA start codon, accompanied by a typical sigma70-type promoter. The mobR gene was expressed in Escherichia coli cells and the recombinant product was purified to homogeneity. Gel mobility-shift assays and DNase I footprinting analyses indicated that MobR binds as a homodimer to an imperfect inverted repeat within the mobA-mobR intergenic region, with an apparent dissociation constant of 11.5(+/- 0.5) nM. The operator site is located between the start codon and the promoter region for mobA, suggesting that MobR functions as a transcriptional repressor for mobA expression. The results of effector-binding assays indicated that MobR, but not its isomers 4-hydroxybenzoate and salicylate, is released from the operator site by the addition of 3-hydroxybenzoate. This dissociation process is highly cooperative, with a Hill coefficient of approximately 2. In addition, CD spectroscopic studies demonstrated that MobR adopts two conformational states corresponding to the effector-bound and unbound forms. These results suggest that the MobR dimer possesses at least two effector-binding sites, and that the effector binding to MobR induces an allosteric conformational change required for dissociation of the protein-DNA complex.

4-Hydroxybenzoate-3-Monooxygenase↗

PubMed2006

Crystal structure of 3-hydroxybenzoate hydroxylase from Comamonas testosteroni has a large tunnel for substrate and oxygen access to the active site.

The 3-hydroxybenzoate hydroxylase (MHBH) from Comamonas testosteroni KH122-3s is a single-component flavoprotein monooxygenase, a member of the glutathione reductase (GR) family. It catalyzes the conversion of 3-hydroxybenzoate to 3,4-dihydroxybenzoate with concomitant requirements for equimolar amounts of NADPH and molecular oxygen. The production of dihydroxy-benzenoid derivative by hydroxylation is the first step in the aerobic degradation of various phenolic compounds in soil microorganisms. To establish the structural basis for substrate recognition, the crystal structure of MHBH in complex with its substrate was determined at 1.8 A resolution. The enzyme is shown to form a physiologically active homodimer with crystallographic 2-fold symmetry, in which each subunit consists of the first two domains comprising an active site and the C-terminal domain involved in oligomerization. The protein fold of the catalytic domains and the active-site architecture, including the FAD and substrate-binding sites, are similar to those of 4-hydroxybenzoate hydroxylase (PHBH) and phenol hydroxylase (PHHY), which are members of the GR family, providing evidence that the flavoprotein aromatic hydroxylases share similar catalytic actions for hydroxylation of the respective substrates. Structural comparison of MHBH with the homologous enzymes suggested that a large tunnel connecting the substrate-binding pocket to the protein surface serves for substrate transport in this enzyme. The internal space of the large tunnel is distinctly divided into hydrophilic and hydrophobic regions. The characteristically stratified environment in the tunnel interior and the size of the entrance would allow the enzyme to select its substrate by amphiphilic nature and molecular size. In addition, the structure of the Xe-derivative at 2.5 A resolution led to the identification of a putative oxygen-binding site adjacent to the substrate-binding pocket. The hydrophobic nature of the xenon-binding site extends to the solvent through the tunnel, suggesting that the tunnel could be involved in oxygen transport.

Amino Acid Sequence↗

PubMed2004

Identification of a novel steroid inducible gene associated with the beta hsd locus of Comamonas testosteroni.

Comamonas testosteroni is a soil bacterium, which can use a variety of steroids as carbon and energy source. Even if it can be estimated that the complete degradation of the steroid nucleus requires more than 20 enzymatic reactions, the complete molecular characterization of the genes encoding these steroid degradative enzymes as well as the genetic organization of them remain to be elucidated. We have previously reported the cloning and nucleotide sequence of two steroid-inducible genes, beta hsd and stdC encoding 3 beta-17 beta-hydroxysteroid dehydrogenase and a hypothetical protein respectively, located in both ends of a 3.2kb HindIII fragment. Herein, we report the cloning and characterization of another steroid-inducible gene, called sip48 (steroid inducible protein), located between these two genes. The analysis of Sip48 amino acid sequence predicts a protein of 438 amino acids with a molecular mass of 48.5 kDa. This protein bears high homology with conserved hypothetical proteins of unknown function described in Pseudomonas aeruginosa, Pseudomonas syringae, Pseudomonas putida, Burkholderia fungorum, Shewanella oneidensis, Pseudomonas fluorescens and Thauera aromatica. The predicted protein shows a typical structure of a leader peptide at its N-terminus. A 48.5 kDa protein encoded by the recombinant plasmid was detected by SDS-PAGE analysis of in vitro [35S]-methionine labeled polypeptides. Analysis of gene expression indicates that Sip48 is tightly controlled at the transcriptional level by several steroid compounds. In addition, transcriptional analysis of sip48 and beta hsd in a sip48 mutant strain, indicates that both genes are transcribed as a polycistronic mRNA. lacZ transcriptional fusions integrated into the chromosome of C. testosteroni demonstrate that a steroid-inducible promoter located upstream of sip48 regulates the expression of both genes.

3-Hydroxysteroid Dehydrogenases↗

PubMed2004

The genes encoding the hydroxylase of 3-hydroxy-9,10-secoandrosta-1,3,5(10)-triene-9,17-dione in steroid degradation in Comamonas testosteroni TA441.

Steroid degradation genes of Comamonas testosteroni TA441 are encoded in at least two gene clusters: one containing the meta-cleavage enzyme gene tesB; and another consisting of ORF18, 17, tesI, H, ORF11, 12, and tesDEFG. TesH and I are, respectively, the Delta(1)- and Delta(4)(5alpha)-dehydrogenase of the 3-ketosteroid, TesD is the hydrolase for the product of meta-cleavage reaction, and TesEFG degrade one of the product of TesD. In this report, we describe the identification of the function of ORF11 (tesA2) and 12 (tesA1). The TesA1- and TesA2-disrupted mutant accumulated two characteristic intermediate compounds, which were identified as 3-hydroxy-9,10-secoandrosta-1,3,5(10)-triene-9,17-dione (3-HSA) and its hydroxylated derivative, 3,17-dihydroxy-9,10-secoandrosta-1,3,5(10)-triene-9,17-dione by MS and NMR analysis. A complementation experiment using a broad-host range plasmid showed that both TesA1 and A2 are necessary for hydroxylation of 3-HSA to 3,4-dihydroxy-9,10-secoandrosta-1,3,5(10)-triene-9,17-dione (3,4-DHSA).

Amino Acid Sequence↗

PubMed2006

ORF18-disrupted mutant of Comamonas testosteroni TA441 accumulates significant amounts of 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid and its derivatives after incubation with steroids.

In a steroid degradation gene cluster of Comamonas testosteroni TA441 consisting of ORF18, 17 and tesIHA2A1DEFG, ORF18 was implicated in encoding a CoA-transferase by database searches, but the matching substrate was not clear. In this study, ORF18 was shown to be necessary for conversion of 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid, a product of hydrolysis of 4,5-9,10-diseco-3-hydroxy-5,9,17-trioxoandrosta-1(10),2-dien-4-oic acid in steroid degradation by TA441. The ORF18-disrupted mutant accumulates 7-hydroxy-9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid and 7,12-dihydroxy-9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid when incubated with chenodeoxycholic acid and cholic acid, respectively.

Chromatography, High Pressure Liquid↗

PubMed2004

Expression, purification, and sequence analysis of catalase-1 from the soil bacterium Comamonas terrigena N3H.

Catalases are essential components of the cellular equipment to cope with oxidative stress. We have purified and characterize herein the most abundant heme-containing catalase-1 from the soil bacterium Comamonas terrigena N3H. This oxidative stress-induced enzyme was isolated from exponential phase cells grown in the presence of peroxyacetic acid. We have used consecutive steps of hydrophobic, molecular sieve, and ion exchange chromatography to achieve a high state of purity for this metalloenzyme. The purified sample of catalase exhibited a specific catalytic activity of 55,900 U/mg, allosteric behavior in peroxidic reaction, a broad pH optimum, and a rather atypical electronic spectrum. The sample of highest purity was subjected to mass spectrometry analysis. The molecular weight of the subunit of this homodimeric protein was determined as 55,417 Da. The Qq-TOF mass analysis method allowed us to sequence short tryptic fragments of this catalase. Five such fragments with a total length of 57 amino acids together with several enzymatic properties allowed the classification of this hydroperoxidase as belonging to clade III of monofunctional catalases. The highest sequence similarity is with the catalase from Vibrio fischeri. The presented results imply the significance of this inducible enzyme in the prevention of toxic effects of oxidative stress for bacterial cells.

Amino Acid Sequence↗

PubMed2006

Treatment of naphthalene-2-sulfonic acid from tannery wastewater by a granular activated carbon fixed bed inoculated with bacterial isolates Arthrobacter globiformis and Comamonas testosteroni.

The kinetics of naphthalene-2-sulfonic acid (2-NSA) adsorption by granular activated carbon (GAC) were measured and the relationships between adsorption, desorption, bioavailability and biodegradation assessed. The conventional Langmuir model fitted the experimental sorption isotherm data and introduced 2-NSA degrading bacteria, established on the surface of the GAC, did not interfere with adsorption. The potential value of GAC as a microbial support in the aerobic degradation of 2-NSA by Arthrobacter globiformis and Comamonas testosteroni was investigated. Using both virgin and microbially colonised GAC, adsorption removed 2-NSA from the liquid phase up to its saturation capacity of 140 mg/g GAC within 48 h. However, between 83.2% and 93.3% of the adsorbed 2-NSA was bioavailable to both bacterial species as a source of carbon for growth. In comparison to the non-inoculated GAC, the combination of rapid adsorption and biodegradation increased the amount (by 70-93%) of 2-NSA removal from the influent phase as well as the bed-life of the GAC (from 40 to >120 d). A microbially conditioned GAC fixed-bed reactor containing 15 g GAC removed 100% 2-NSA (100 mg/l) from tannery wastewater at an empty bed contact time of 22 min for a minimum of 120 d without the need for GAC reconditioning or replacement. This suggests that small volume GAC bioreactors could be used for tannery wastewater recycling.

Adsorption↗

PubMed2002

Identification of a novel Comamonas testosteroni gene encoding a steroid-inducible extradiol dioxygenase.

Comamonas testosteroni is a Gram-negative bacterium that can grow on steroids and polycyclic aromatic hydrocarbons (PAH) as sole carbon and energy source. Complete mineralisation of these compounds is achieved through complex metabolic pathways comprising a set of inducible enzymes. Whereas the degradation pathways for PAHs have been intensively studied, patterns of enzymes leading to ring fissions of the steroid nucleus are unclear. Several intermediates of the steroid and PAH degradation pathways have similar structures therefore the question remains of whether both classes are substrates of different degradation routes or whether some catabolic enzymes function in both pathways. Interestingly, our studies reveal that testosterone simultaneously induces the expression of steroid- and PAH-catabolising enzymes in C. testosteroni. By cloning the gene, one of these testosterone-inducible proteins (TIP1) turned out to be biphenyl-2,3-diol-1,2-dioxygenase. This enzyme has been described to convert 2,3-dihydroxybiphenyl into 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid in PAH degradation. The gene was found on a cluster encoding TIP1, three orfs, and another testosterone-inducible protein (TIP6) of unknown function. The deduced amino acid sequence of TIP1 revealed that the enzyme contains 299 amino acids (34 kDa) and shares homologies to a variety of other extradiol dioxygenases. Based on the similar catechol moieties in PAH and steroid intermediates, together with its inducibility by testosterone, it is conceivable that TIP1 functions as a steroid extradiol dioxygenase to convert steroidal secocatechols into the disecoandrostanes. Our data suggest a role of the reported TIP1 protein in both the degradation pathways for steroids and aromatic hydrocarbons.

Amino Acid Sequence↗