Biomedical subjects

Hong Liu

Publications and source records attributed to Hong Liu.

At least 37 records · Page 2Linked to original sources

PubMed2006

Flow-through multianalyte chemiluminescent immunosensing system with designed substrate zone-resolved technique for sequential detection of tumor markers.

A novel flow-through immunosensing system for performing a multianalyte chemiluminescent determination in a single run was designed. A new analytical strategy of substrate zone-resolved technique was proposed. Using carcinoma antigen 125 (CA 125) and carcinoembryonic antigen (CEA) as model analytes, the capture antibodies for CA 125 and CEA were immobilized on an UltraBind aldehyde-activated membrane to act as an immunoreactor, to which the mixture of CA 125, CEA, and their corresponding tracers, horseradish peroxidase (HRP)-labeled anti-CA 125 and alkaline phosphatase (ALP)-labeled anti-CEA, was introduced for on-line incubation. The substrates for HRP and ALP were then delivered into the detection cell sequentially to perform substrate zone-resolved immunoassay by a sandwich format. Under optimal conditions, CA 125 and CEA could be assayed in the ranges of 5.0-100 units/mL and 1.0-120 ng/mL, respectively. The whole assay process including incubation, wash, detection, and regeneration could be completed in 35 min. The serum samples from the clinic were assayed with the proposed method, and the results were in acceptable agreement with the reference values. This method and the strategy of substrate zone-resolved technique could be further developed for high-throughput multianalyte immunoassay.

Biomarkers, Tumor↗

PubMed2006

Chitosan-based controlled porosity osmotic pump for colon-specific delivery system: screening of formulation variables and in vitro investigation.

A microbially triggered colon-targeted osmotic pump (MTCT-OP) has been studied. The gelable property at acid condition and colon-specific biodegradation of chitosan were used to: (1) produce the osmotic pressure, (2) form the drug suspension and (3) form the in situ delivery pores for colon-specific drug release, respectively. The scanning electron microscopy (SEM) study and the calculation of membrane permeability were applied to elucidate the mechanism of MTCT-OP. The effects of different formulation variables, including the level of pH-regulating excipient (citric acid) and the amount of chitosan in the core, the weight gain of semipermeable membrane and enteric-coating membrane, and the level of pore former (chitosan) in the semipermeable membrane, have been studied. Results of SEM showed that the in situ delivery pores could be formed in predetermined time after coming into contact with dissolution medium, and the number of pore was dependent on the initial level of pore former in the membrane. The amount of budesonide release was directly proportional to the initial level of pore former, but inversely related to the weight of semipermeable membrane. The effects of variations in the level of citric acid and chitosan in the core formulation on drug release were studied. The different levels of enteric-coating membrane could prevent cellulose acetate membrane (containing chitosan as pore former) from forming pore or rupture before contact with simulated colonic fluid, but had no effect on the drug release. Budesonide release from the developed formulation was inversely proportional to the osmotic pressure of the release medium, confirming that osmotic pumping was the major mechanism of drug release. These results showed that MTCT-OP based on osmotic technology and microbially triggered mechanism had a high potential for colon-specific drug delivery.

Animals↗

PubMed2006

Investigation of the role of cytochrome P450 2B4 active site residues in substrate metabolism based on crystal structures of the ligand-bound enzyme.

Based on the X-ray crystal structures of 4-(4-chlorophenyl)imidazole (4-CPI)- and bifonazole (BIF)-bound P450 2B4, eight active site mutants at six positions were created in an N-terminal modified construct termed 2B4dH and characterized for enzyme inhibition and catalysis. I363A showed a >4-fold decrease in differential inhibition by BIF and 4-CPI (IC(50,BIF)/IC(50,4-CPI)). F296A, T302A, I363A, V367A, and V477A showed a 2-fold decreased k(cat) for 7-ethoxy-4-trifluoromethylcoumarin O-deethylation, whereas V367A and V477F showed an altered K(m). T302A, V367L, and V477A showed >4-fold decrease in total testosterone hydroxylation, whereas I363A, V367A, and V477F showed altered stereo- and regioselectivity. Interestingly, I363A showed a 150-fold enhanced k(cat)/K(m) with testosterone, and yielded a new metabolite. Furthermore, testosterone docking into three-dimensional models of selected mutants based on the 4-CPI-bound structure suggested a re-positioning of residues 363 and 477 to yield products. In conclusion, our results suggest that the 4-CPI-bound 2B4dH/H226Y crystal structure is an appropriate model for predicting enzyme catalysis.

Amino Acid Substitution↗

PubMed2006

Engineering of cytochrome P450 3A4 for enhanced peroxide-mediated substrate oxidation using directed evolution and site-directed mutagenesis.

CYP3A4 has been subjected to random and site-directed mutagenesis to enhance peroxide-supported metabolism of several substrates. Initially, a high-throughput screening method using whole cell suspensions was developed for H2O2-supported oxidation of 7-benzyloxyquinoline. Random mutagenesis by error-prone polymerase chain reaction and activity screening yielded several CYP3A4 mutants with enhanced activity. L216W and F228I showed a 3-fold decrease in Km, HOOH and a 2.5-fold increase in kcat/Km, HOOH compared with CYP3A4. Subsequently, T309V and T309A were created based on the observation that T309V in CYP2D6 has enhanced cumene hydroperoxide (CuOOH)-supported activity. T309V and T309A showed a > 6- and 5-fold higher kcat/Km, CuOOH than CYP3A4, respectively. Interestingly, L216W and F228I also exhibited, respectively, a > 4- and a > 3-fold higher kcat/Km, CuOOH than CYP3A4. Therefore, several multiple mutants were constructed from rationally designed and randomly isolated mutants; among them, F228I/T309A showed an 11-fold higher kcat/Km, CuOOH than CYP3A4. Addition of cytochrome b5, which is known to stimulate peroxide-supported activity, enhanced the kcat/Km, CuOOH of CYP3A4 by 4- to 7-fold. When the mutants were tested with other substrates, T309V and T433S showed enhanced kcat/Km, CuOOH with 7-benzyloxy-4-(trifluoromethyl)coumarin and testosterone, respectively, compared with CYP3A4. In addition, in the presence of cytochrome b5, T433S has the potential to produce milligram quantities of 6beta-hydroxytestosterone through peroxide-supported oxidation. In conclusion, a combination of random and site-directed mutagenesis approaches yielded CYP3A4 enzymes with enhanced peroxide-supported metabolism of several substrates.

Benzene Derivatives↗

PubMed2006

Inhibitor discovery targeting the intermediate structure of beta-amyloid peptide on the conformational transition pathway: implications in the aggregation mechanism of beta-amyloid peptide.

Abeta peptides cleaved from the amyloid precursor protein are the main components of senile plaques in Alzheimer's disease. Abeta peptides adopt a conformation mixture of random coil, beta-sheet, and alpha-helix in solution, which makes it difficult to design inhibitors based on the 3D structures of Abeta peptides. By targeting the C-terminal beta-sheet region of an Abeta intermediate structure extracted from molecular dynamics simulations of Abeta conformational transition, a new inhibitor that abolishes Abeta fibrillation was discovered using virtual screening in conjunction with thioflavin T fluorescence assay and atomic force microscopy determination. Circular dichroism spectroscopy demonstrated that the binding of the inhibitor increased the beta-sheet content of Abeta peptides either by stabilizing the C-terminal beta-sheet conformation or by inducing the intermolecular beta-sheet formation. It was proposed that the inhibitor prevented fibrillation by blocking interstrand hydrogen bond formation of the pleated beta-sheet structure commonly found in amyloid fibrils. The study not only provided a strategy for inhibitor design based on the flexible structures of amyloid peptides but also revealed some clues to understanding the molecular events involved in Abeta aggregation.

Amyloid↗

PubMed2006

Sensitive quantification of ranolazine in human plasma by liquid chromatography--tandem mass spectrometry with positive electrospray ionization.

A rapid, selective and sensitive liquid chromatography-tandem mass spectrometry (LC-MS-MS) method with positive electrospray ionization (ESI) was developed for the quantification of ranolazine in human plasma. After liquid-liquid extraction of ranolazine and internal standard (ISTD) phenoprolamine from a 100 microl specimen of plasma, HPLC separation was achieved on a Nova-Pak C(18) column, using acetonitrile-water-formic acid-10% n-butylamine (70:30:0.5:0.08, v/v/v/v) as the mobile phase. The mass spectrometer was operated in multiple reaction monitoring (MRM) mode using the transition m/z 428.5-->m/z 279.1 for ranolazine and m/z 344.3-->m/z 165.1 for the internal standard, respectively. Linear calibration curves were obtained in the concentration range of 5-4000 ng/ml, with a lower limit of quantitation (LLOQ) of 5 ng/ml. The intra- and inter-day precision values were below 3.7% and accuracy was within +/-3.2% at all three quality control (QC) levels. This method was found suitable for the analysis of plasma samples collected during the phase I pharmacokinetic studies of ranolazine performed in 28 healthy volunteers after single oral doses from 200 mg to 800 mg.

Acetanilides↗

PubMed2006

Evolutionary diversity of ketoacyl synthases in cellulolytic myxobacterium Sorangium.

The diversity of type I polyketide synthases (PKSs) in cellulolytic myxobacterium Sorangium was explored by assaying the ketoacyl synthases (KSs) in 10 Sorangium strains with two degenerate primer sets and 64 different KS fragments were obtained. For their deduced amino acid sequences, eight were identical to three known KSs from Sorangium and Magnetospirillum, while the others showed 54-83% identities to the modular KS domains reported from various microorganisms. Parts of the Sorangium KSs tightly share the clade with Actinobacteria excluding any other analyzed myxobacterial KSs, or with Cyanobacteria /Myxobacteria. Parts are widely located in the three functional groups - "Loading", "NRPS/PKS" and "Trans-AT". Sorangium KSs in the Actinobacteria, Cyanobacteria/Myxobacteria, or "Loading" clade further evolved independently on its own genus. Notably, the modular KSs from other Myxobacteria genera, i.e. Myxococcus, Stigmatella, Melittangium, Cystobacter and Angiococcus are often distributed crosswise and form non-Sorangium blend subgroups. "NRPS/PKS" and "Trans-AT" are two rather diverse groups and the Sorangium KSs in these clades evolved crosswise with other taxa lineages. The results presented in this paper suggest that the inherent genetic strategies, together with frequent gene importing from many organisms (HGT) have contributed to the evolution of modular PKSs in Sorangium. These findings reinforce that Sorangium strains are really excellent creators for novel and diverse polyketides.

Evolution, Molecular↗

PubMed2006

Effects of mutation at the D-JH junction on affinity, specificity, and idiotypy of anti-progesterone antibody DB3.

The crystal structures of the Fab' fragment of the anti-progesterone monoclonal antibody DB3 and its complexes with steroid haptens have shown that the D-JH junctional residue TrpH100 is a key contributor to binding site interactions with ligands. The indole group of TrpH100 also undergoes a significant conformational change between the bound and unliganded states, effectively opening and closing the combining site pocket. In order to explore the effect of substitutions at this position on steroid recognition, we have carried out mutagenesis on a construct encoding a three-domain single-chain fragment (VH/K) of DB3 expressed in Escherichia coli. TrpH100 was replaced by 13 different amino acids or deleted, and the functional and antigenic properties of the mutated fragments were analyzed. Most substitutions, including small, hydrophobic, hydrophilic, neutral, and negatively charged side chains, were reduced or abolished binding to free progesterone, although binding to progesterone-BSA was partially retained. The reduction in antigen binding was paralleled by alteration of the idiotype associated with the DB3 combining site. In contrast, the replacement of TrpH100 by Arg produced a mutant that retained wild-type antibody affinity and idiotype, but with altered specificity. Significant changes in this mutant included increased relative affinities of 10(4)-fold for progesterone-3-carboxymethyloxime and 10-fold for aetiocholanolone. Our results demonstrate an essential role for the junctional residue H100 in determining steroid-binding specificity and combining site idiotype and show that these properties can be changed by a single amino acid substitution at this position.

Amino Acid Sequence↗

PubMed2006

Arylaminoethyl carbamates as a novel series of potent and selective cathepsin S inhibitors.

We report a novel series of noncovalent inhibitors of cathepsin S. The synthesis of the peptidomimetic scaffold is described and structure-activity relationships of P3, P1, and P1' subunits are discussed. Lead optimization to a non-peptidic scaffold has resulted in a new class of potent, highly selective, and orally bioavailable cathepsin S inhibitors.

Administration, Oral↗

PubMed2006

Synthesis and SAR of arylaminoethyl amides as noncovalent inhibitors of cathepsin S: P3 cyclic ethers.

The synthesis and structure-activity relationship of a series of arylaminoethyl amide cathepsin S inhibitors are reported. Optimization of P3 and P2 groups to improve overall physicochemical properties resulted in significant improvements in oral bioavailability over early lead compounds. An X-ray structure of compound 37 bound to the active site of cathepsin S is also reported.

Administration, Oral↗

PubMed2006

Syntheses of triazole-modified zanamivir analogues via click chemistry and anti-AIV activities.

Sixteen novel 4-triazole-modified zanamivir (1) analogues were synthesized using the click reactions, and their inhibitory activities against avian influenza virus (AIV, H5N1) were determined. Compound 3b exerts promising inhibitory activity with EC(50) of 6.4 microM, which is very close to that of zanamivir (EC(50) = 2.8 microM). Molecular modeling provided the information about the binding model between inhibitors and neuraminidase, which are in good agreement with inhibitory activities.

Antiviral Agents↗

PubMed2006

Activation of activating transcription factor 2 by p38 MAP kinase during apoptosis induced by human amylin in cultured pancreatic beta-cells.

Amylin-mediated islet beta-cell death is implicated in diabetogenesis. We previously reported that fibrillogenic human amylin (hA) evokes beta-cell apoptosis through linked activation of Jun N-terminal kinase 1 (JNK 1) and a caspase cascade. Here we show that p38 kinase [p38 mitogen-activated protein (MAP) kinase] became activated by hA treatment of cultured beta-cells whereas extracellular signal-regulated kinase (ERK) did not; by contrast, nonfibrillogenic rat amylin (rA) altered neither. Pretreatment with the p38 kinase-inhibitor SB203580 decreased hA-induced apoptosis and caspase-3 activation by approximately 30%; as did combined SB203580 and JNK inhibitor I, by about 70%; and the combination of SB203580, the JNK inhibitor I and a caspase-8 inhibitor, by 100%. These findings demonstrate the requirement for concurrent activation of the p38 kinase, JNK and caspase-8 pathways. We further showed that hA elicits time-dependent activation of activating transcription factor 2 (ATF-2), which was largely suppressed by SB203580, indicating that this activation is catalyzed mainly by p38 kinase. Furthermore, hA-induced apoptosis was suppressed by specific antisense ATF-2, and increased phospho-ATF-2 (p-ATF-2) was associated with increased CRE (cAMP-response element) DNA binding and CRE-mediated transcriptional activity, as well as enhancement of c-jun promoter activation. We also detected changes in the phosphorylation status and composition of the CRE complex that may play important roles in regulation of distinct downstream target genes. These studies establish p38 MAP kinase-mediated activation of ATF-2 as a significant mechanism in hA-evoked beta-cell death, which may serve as a target for pharmaceutical intervention and effective suppression of beta-cell failure in type-2 diabetes.

Activating Transcription Factor 2↗

PubMed2006

Connective tissue growth factor is associated with the early renal hypertrophy in uninephrectomized diabetic rats.

BACKGROUND: Renal hypertrophy has been regarded as the early feature of diabetic nephropathy (DN), which may eventually lead to proteinuria and renal fibrosis. However, the exact mechanism of renal hypertrophy is still unclear. The aim of this study was to investigate the possible association of connective tissue growth factor (CTGF) with renal hypertrophy in uninephrectomized diabetic rats. METHODS: Seventy-two Sprague-Dawley (SD) rats were randomly divided into two groups: control group (group C, n = 32) and diabetic nephropathy (group DN, n = 40). Each group was re-divided into 4 subgroups according to the experimental period. The rats were sacrificed at 1, 2, 4, and 8 weeks respectively after induction of diabetes. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ) after rats had received uninephrectomy. Blood glucose (BG), body weight (BW), 24-h urinary albumin excretion (24hUalb), kidney weight (KW), KW/BW, glomerular tuft area (AG), glomerular tuft volume (VG), proximal tubular area (AT) at each time point, the width of glomerular basement membrane (GBM) and tubular basement membrane (TBM) at week 8 were measured when the rats were sacrificed. Renal expression of CTGF and p27kip1 were detected by immunohistochemical staining. The relationship between CTGF expression and increasing of VG and AT was analyzed. RESULTS: There was a significant increase of 24hUalb, KW, and KW/BW from week 1 onward in diabetic rats compared to those in group C (P < 0.05, respectively), diabetic rats also had a significant increase of AG, VG, and AT from week 1 onward. It was also shown that diabetic rats had a thickening of GBM [(245.7 +/- 103.0) nm vs (121.8 +/- 19.1) nm, P < 0.01] and TBM [(767.7 +/- 331.1) nm vs (293.0 +/- 110.5) nm, P < 0.01] at week 8. There was a weak expression for CTGF and p27kip1 in normal glomeruli and tubuli, while a significant increasing expression of CTGF and p27kip1 was found in glomeruli and tubuli in diabetic kidney from week 1 onward (P < 0.05, respectively), and the extent of CTGF expression was positively correlated with AG (r = 0.92, P < 0.05), VG (r = 0.86, P < 0.05), AT (r = 0.94, P < 0.01) and positively correlated with the expression of p27kip1 (r = 0.96, P < 0.01). CONCLUSION: The expression of CTGF increases in diabetic rat kidney at the early stage, which might be an important mediator of renal hypertrophy through arresting cell cycling.

Albuminuria↗

PubMed2006

One novel quinoxaline derivative as a potent human cyclophilin A inhibitor shows highly inhibitory activity against mouse spleen cell proliferation.

Cyclophilin A (CypA) is a ubiquitous cellular enzyme playing critical roles in many biological processes, and its inhibitor has been reported to have potential immunosuppressive activity. In this work, we reported a novel quinoxaline derivative, 2,3-di(furan-2-yl)-6-(3-N,N-diethylcarbamoyl-piperidino)carbonylamino quinoxaline (DC838, 3), which was confirmed to be a potent inhibitor against human CypA. By using the surface plasmon resonance (SPR) and fluorescence titration techniques, the kinetic analysis of CypA/DC838 interaction was quantitatively performed. CypA peptidyl prolyl cis-trans isomerase (PPIase) activity inhibition assay showed that DC838 demonstrated highly CypA PPIase inhibitory activity. In vivo assay results showed that DC838 could inhibit mouse spleen cell proliferation induced by concanavalin A (Con A). Molecular docking simulation further elucidated the specific DC838 binding to CypA at the atomic level. The current work should provide useful information in the discovery of immunosuppressor based on CypA inhibitor.

Animals↗

PubMed2006

Characterization of genes involved in the initial reactions of 4-chloronitrobenzene degradation in Pseudomonas putida ZWL73.

The genes encoding enzymes involved in the initial reactions during degradation of 4-chloronitrobenzene (4CNB) were characterized from the 4CNB utilizer Pseudomonas putida ZWL73, in which a partial reductive pathway was adopted. A DNA fragment containing genes coding for chloronitrobenzene nitroreductase (CnbA) and hydroxylaminobenzene mutase (CnbB) were PCR-amplified and subsequently sequenced. These two genes were actively expressed in Escherichia coli, and recombinant E. coli cells catalyzed the conversion of 4CNB to 2-amino-5-chlorophenol, which is the ring-cleavage substrate in the degradation of 4CNB. Phylogenetic analyses on sequences of chloronitrobenzene nitroreductase and hydroxylaminobenzene mutase revealed that these two enzymes are closely related to the functionally identified nitrobenzene nitroreductase and hydroxylaminobenzene mutase from Pseudomonas strains JS45 and HS12. The nitroreductase from strain ZWL73 showed a higher specific activity toward 4CNB than nitrobenzene (approximately at a ratio of 1.6:1 for the recombinant or 2:1 for the wild type), which is in contrast to the case where the nitroreductase from nitrobenzene utilizers Pseudomonas pseudoalcaligenes JS45 with an apparently lower specific activity against 4CNB than nitrobenzene (0.16:1) [Kadiyala et al. Appl Environ Microbiol 69:6520-6526, 2003]. This suggests that the nitroreductase from 4-chloronitrobenzene utilizer P. putida ZWL73 may have evolved to prefer chloronitrobenzene to nitrobenzene as its substrate.

Bacterial Proteins↗

PubMed2006

COX-2 contributes to the maintenance of flow-induced dilation in arterioles of eNOS-knockout mice.

Our previous studies demonstrated that, in gracilis muscle arterioles of male mice deficient in the gene for endothelial nitric oxide synthase (eNOS), flow-induced dilation (FID) is mediated by endothelial PGs. Thus the present study aimed to identify the specific isoform of cyclooxygenase (COX) responsible for the compensatory mediation of FID in arterioles of eNOS-knockout (KO) mice. Experiments were conducted on gracilis muscle arterioles of male eNOS-KO and wild-type (WT) mice. Basal tone and magnitude of FID of arterioles were comparable in the two strains of mice. A role for COX isoforms in the mediation of the responses was assessed by use of valeryl salicylate (3 mM) and NS-398 (10 microM), inhibitors of COX-1 and COX-2, respectively. In eNOS-KO arterioles, valeryl salicylate or NS-398 alone inhibited FID (at maximal flow rate) by approximately 51% and approximately 58%, respectively. Administration of both inhibitors eliminated the dilation. In WT arterioles, inhibition of COX-2 did not significantly affect FID, whereas inhibition of COX-1 decreased the dilation by approximately 57%. The residual portion of the response was abolished by additional administration of Nomega-nitro-L-arginine methyl ester. Western blot analysis indicated a comparable content of COX-1 protein in arterioles of WT and eNOS-KO mice. COX-2 protein, which was not detectable in arterioles of WT mice, was strongly expressed in arterioles of eNOS-KO mice, together with an upregulation of COX-2 gene expression. Immunohistochemical staining confirmed the presence of COX-2 in the endothelium of eNOS-KO arterioles. In conclusion, COX-2-derived PGs are the mediators responsible for maintenance of FID in arterioles of eNOS-deficient mice.

Animals↗

PubMed2006

Distinct binding of cholesterol and 5beta-cholestane-3alpha,7alpha,12alpha-triol to cytochrome P450 27A1: evidence from modeling and site-directed mutagenesis studies.

Cytochrome P450 27A1 (P450 27A1 or CYP27A1) is an important enzyme that participates in different pathways of cholesterol degradation as well as in the activation of vitamin D(3). Several approaches were utilized to investigate how two physiological substrates, cholesterol and 5beta-cholestane-3alpha,7alpha,12alpha-triol, interact with CYP27A1. The enzyme active site was first probed spectrally by assessing binding of the two substrates and five substrate analogues followed by computer modeling and site-directed mutagenesis. The computer models suggest that the spatial positions and orientations of cholesterol and 5beta-cholestane-3alpha,7alpha,12alpha-triol are different in the enzyme active site. As a result, some of the active site residues interact with both substrates, although they are situated differently relative to each steroid, and some residues bind only one substrate. Mutation of the overlapping substrate-contact residues (W100, H103, T110, M301C, V367, I481, and V482) affected CYP27A1 binding and enzyme activity in a substrate-dependent manner and allowed identification of several important side chains. T110 is proposed to interact with the 12alpha-hydroxyl of 5beta-cholestane-3alpha,7alpha,12alpha-triol, whereas V367 seems to be crucial for correct positioning of the cholesterol C26 methyl group and for regioselective hydroxylation of this substrate. Distinct binding of the CYP27A1 substrates may provide insight into why phenotypic manifestations of cerebrotendinous xanthomatosis, a disease associated with CYP27A1 deficiency, are so diverse.

Amino Acid Sequence↗

PubMed2006

Plasmid-mediated degradation of 4-chloronitrobenzene by newly isolated Pseudomonas putida strain ZWL73.

A strain of Pseudomonas putida ZWL73 was isolated from soil contaminated with chloronitrobenzenes and identified by 16S rDNA sequencing. This bacterium released chloride and ammonia into the medium when grown on 4-chloronitrobenzene (4CNB) as the sole source of carbon, nitrogen and energy. A plasmid designated pZWL73 of approximately 100 kb in this strain was found to be responsible for 4CNB degradation. This was based on the fact that the plasmid-cured strains showed 4CNB- phenotype and the 4CNB+ phenotype could be conjugally transferred. The cell-free extracts of strain ZWL73 exhibited chloronitrobenzene nitroreductase and 2-amino-5-chlorophenol 1, 6-dioxygenase (2A5CPDO) activities, but neither activity was found from that of the plasmid-cured strain. We have also cloned a 4.9-kb EcoRI fragment exhibiting 2A5CPDO activity. Sequencing results revealed beta-subunit (cnbCa) and alpha subunit (cnbCb) of a meta-cleavage dioxygenase, which were subsequently expressed in E. coli with 2A5CPDO activity. The phylogenetic analysis suggested that 2A5CPDO may form a new subgroup in class III meta-cleavage dioxygenase with its close homologs.

Biodegradation, Environmental↗