Dihydroorotate dehydrogenase is a flavin-dependent mitochondrial enzyme to catalyze the fourth step of the de novo synthesis of pyrimidine and to oxidize dihydroorotate to orotate. By selectively inhibiting dihydroorotate dehydrogenase, thereby inhibiting pyrimidine synthesis, the enzyme has been developed for the treatment of cancer, autoimmune diseases, bacterial or viral infections, parasitic diseases and so on. The development of inhibitory drugs requires a detailed understanding of the structural characteristics and catalytic cycle mechanism of dihydroorotate dehydrogenase. Therefore, this paper reviews these two aspects, and indicates perspectives of these inhibitors in clinical application.
Catalysis ; Mitochondria/metabolism* ; Oxidation-Reduction ; Oxidoreductases Acting on CH-CH Group Donors/metabolism*

BACKGROUND: Late-onset multiple acyl-coA dehydrogenase deficiency (MADD) is an autosomal recessive inherited metabolic disorder. It is still unclear about the muscle magnetic resonance image (MRI) pattern of the distal lower limb pre- and post-treatment in patients with late-onset MADD. This study described the clinical and genetic findings in a cohort of patients with late-onset MADD, and aimed to characterize the MRI pattern of the lower limbs. METHODS: Clinical data were retrospectively collected from clinic centers of Peking University People's Hospital between February 2014 and February 2018. Muscle biopsy, blood acylcarnitines, and urine organic acids profiles, and genetic analysis were conducted to establish the diagnosis of MADD in 25 patients. Muscle MRI of the thigh and leg were performed in all patients before treatment. Eight patients received MRI re-examinations after treatment. RESULTS: All patients presented with muscle weakness or exercise intolerance associated with variants in the electron transfer flavoprotein dehydrogenase gene. Muscle MRI showed a sign of both edema-like change and fat infiltration selectively involving in the soleus (SO) but sparing of the gastrocnemius (GA) in the leg. Similar sign of selective involvement of the biceps femoris longus (BFL) but sparing of the semitendinosus (ST) was observed in the thigh. The sensitivity and specificity of the combination of either "SO+/GA-" sign or "BFL+/ST-" sign for the diagnosis of late-onset MADD were 80.0% and 83.5%, respectively. Logistic regression model supported the findings. The edema-like change in the SO and BFL muscles were quickly recovered at 1 month after treatment, and the clinical symptom was also relieved. CONCLUSIONS This study expands the clinical and genetic spectrums of late-onset MADD. Muscle MRI shows a distinct pattern in the lower limb of patients with late-onset MADD. The dynamic change of edema-like change in the affected muscles might be a potential biomarker of treatment response.
Adolescent ; Adult ; Biopsy ; methods ; Carnitine ; analogs & derivatives ; blood ; Electron-Transferring Flavoproteins ; genetics ; Female ; Hamstring Muscles ; diagnostic imaging ; metabolism ; pathology ; Humans ; Iron-Sulfur Proteins ; genetics ; Magnetic Resonance Imaging ; methods ; Male ; Middle Aged ; Multiple Acyl Coenzyme A Dehydrogenase Deficiency ; diagnostic imaging ; genetics ; pathology ; Muscle, Skeletal ; diagnostic imaging ; metabolism ; pathology ; Oxidoreductases Acting on CH-NH Group Donors ; genetics ; Retrospective Studies ; Young Adult

OBJECTIVE: To detect potential variation in an ethnic Han Chinese family affected with late-onset lipid storage myopathy. METHODS: Next generation sequencing (NGS) was used to screen disease-related genes in the proband. Suspected mutation was validated with PCR and Sanger sequencing in two patients, their father, and 100 healthy controls. RESULTS: Heterozygous c.770A>G (p.Tyr257Cys) and c.1395dupT (p.Gly466Tryfs) mutation were detected in the two patients. Their father was found to be heterozygous for the c.770A>G (p.Tyr257Cys) mutation, while the c.1395dupT (p.Gly466Tryfs) variation was not reported previously and not found among the healthy controls. CONCLUSION Mutations of the ETFDH gene probably underlie the pathogenesis in this family. The novel c.1395dupT (p.Gly466Tryfs) has enriched the mutation spectrum of EDFDH gene.
Asian Continental Ancestry Group ; Electron-Transferring Flavoproteins ; genetics ; Heterozygote ; High-Throughput Nucleotide Sequencing ; Humans ; Iron-Sulfur Proteins ; genetics ; Lipid Metabolism, Inborn Errors ; genetics ; Muscular Dystrophies ; genetics ; Mutation ; Oxidoreductases Acting on CH-NH Group Donors ; genetics

OBJECTIVETo identify pathogenic mutation in a boy affected with riboflavin responsive-multiple acyl-CoA dehydrogenase deficiency (RR-MADD).

METHODSThe patient was initially diagnosed as primary carnitine deficiency (PCD) and has been treated with carnitine supplementation for 7 years. Clinical manifestations and characteristics of fibula muscle specimen were analyzed. Potential mutation in electron transfer flavoprotein dehydrogenase (ETFDH) gene (for the patient and his parents) and carnitine transfer protein gene (SLC22A5) (for the patient) was screened.

RESULTSElectronic microscopy of the muscle specimen has suggested lipid storage myopathy. Mutation analysis has found that the patient carried compound heterozygous mutations, c.250G>A and c.380T>C, in exon 3 of the ETFDH gene, whilst his father and mother were heterozygous for the c.380T>C and c.250G>A mutations, respectively. Screening of the SLC22A5 gene has yielded no clinically meaningful result. After the establishment of diagnosis of RR-MADD, the condition of the patient has improved greatly with supplementation of high doses of riboflavin along with continuous carnitine supplement.

CONCLUSIONThe c.250G>A (p.Ala84Thr) mutation of exon 3 of the ETFDH gene has been a hot spot in Southern Chinese population, whilst the c.380T>C (p.Leu127Pro) is rarely reported. Our case has suggested that therapeutic diagnosis cannot substitute genetic testing. The mechanism for having stabilized the patient with only carnitine supplementation for 7 years needs further investigation.

Adolescent ; Adult ; Base Sequence ; Child ; DNA Mutational Analysis ; Electron-Transferring Flavoproteins ; genetics ; metabolism ; Female ; Humans ; Iron-Sulfur Proteins ; genetics ; metabolism ; Male ; Molecular Sequence Data ; Multiple Acyl Coenzyme A Dehydrogenase Deficiency ; enzymology ; genetics ; metabolism ; Muscle, Skeletal ; metabolism ; Organic Cation Transport Proteins ; genetics ; metabolism ; Oxidoreductases Acting on CH-NH Group Donors ; genetics ; metabolism ; Riboflavin ; metabolism ; Solute Carrier Family 22 Member 5

Biliverdin reductase A (BLVRA), an enzyme that converts biliverdin to bilirubin, has recently emerged as a key regulator of the cellular redox cycle. However, the role of BLVRA in the aging process remains unclear. To study the role of BLVRA in the aging process, we compared the stress responses of young and senescent human diploid fibroblasts (HDFs) to the reactive oxygen species (ROS) inducer, hydrogen peroxide (H2O2). H2O2 markedly induced BLVRA activity in young HDFs, but not in senescent HDFs. Additionally, depletion of BLVRA reduced the H2O2-dependent induction of heme oxygenase-1 (HO-1) in young HDFs, but not in senescent cells, suggesting an aging-dependent differential modulation of responses to oxidative stress. The role of BLVRA in the regulation of cellular senescence was confirmed when lentiviral RNAitransfected stable primary HDFs with reduced BLVRA expression showed upregulation of the CDK inhibitor family members p16, p53, and p21, followed by cell cycle arrest in G0-G1 phase with high expression of senescence-associated beta-galactosidase. Taken together, these data support the notion that BLVRA contributes significantly to modulation of the aging process by adjusting the cellular oxidative status.
Age Factors ; Blotting, Western ; *Cell Aging ; Cell Cycle ; Cells, Cultured ; Enzyme Induction ; Fibroblasts/physiology ; G1 Phase ; Heme Oxygenase-1/metabolism ; Humans ; Hydrogen Peroxide/pharmacology ; *Oxidative Stress ; Oxidoreductases Acting on CH-CH Group Donors/*metabolism ; Protein Kinase Inhibitors/metabolism ; RNA, Small Interfering ; Reactive Oxygen Species/metabolism ; beta-Galactosidase/genetics/metabolism

The methanol poisoning by oral intake or skin contact occurs occasionally, which may have serious consequences including blindness and/or death. Methanol and its metabolites, formaldehyde and formic acid, are associated with metabolic acidosis, visual dysfunction and neurological symptoms. At present, the mechanism of methanol poisoning primarily focuses on the cell hypoxia, the alteration of structure and biological activity induced by free radical and lactic acid. Meanwhile, methanol poisoning causes changes in the balance between the production of free radicals and antioxidant capacity and in the proteases-protease inhibitors system, which lead to a series of disturbances.
Acidosis/chemically induced* ; Animals ; Formaldehyde/poisoning* ; Formates/poisoning* ; Free Radicals/metabolism* ; Humans ; Methanol/poisoning* ; Nervous System/pathology* ; Oxidoreductases Acting on CH-NH Group Donors/metabolism* ; Proteins/metabolism* ; Vision Disorders/pathology*

BACKGROUNDThe critical roles of polyamines in cell growth and differentiation have made polyamine metabolic pathway a promising target for antitumor therapy. Recent studies have demonstrated in vitro that some antitumor polyamine analogues could be used as substrates and oxidized by purified recombinant human N(1)-acetylpolyamine oxidase (APAO, an enzyme that catabolizes natural polyamines), indicating a potential role of APAO in determining the sensitivity of cancer cells to specific antitumor analogues. This study evaluated, in vivo, the effect of APAO on cytotoxicity of antitumor polyamine analogue, N(1)-cyclopropylmethyl-N(11)-ethylnorspermine (CPENS) and its mechanism when highly expressed in human lung cancer line A549.

METHODSA clone with high expression of APAO was obtained by transfecting A549 lung cancer cell line with pcDNA3.1/APAO plasmid and selecting with quantitative realtime PCR and APAO activity assay. Cell proliferation was determined by MTT method and apoptosis related events were evaluated by DNA fragmentation, sub-G1/flow cytometric assay, western blotting (for cytochrome C and Bax) and colorimetric assay (for casapse-3 activity).

RESULTSA clone highly expressing APAO was obtained. High expression of APAO in A549 cells inhibited accumulation of CPENS, decreased their sensitivity to the toxicity of CPENS and prevented CPENS induced apoptosis.

CONCLUSIONThese results indicate a new drug resisting, mechanism in the tumor cells. High expression of APAO can greatly decrease the sensitivity of tumor cells to the specific polyamine analogues by detoxifying those analogues and prevent analogue induced apoptosis.

Apoptosis ; drug effects ; Blotting, Western ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Flow Cytometry ; Humans ; Oxidoreductases Acting on CH-NH Group Donors ; genetics ; metabolism ; Polyamines ; metabolism ; pharmacology ; Reverse Transcriptase Polymerase Chain Reaction

Lignans are important defensive compounds in plants and have good biological activities protecting human health. In order to study the medicinal secondary metabolism of Fagopyrum cymosum (Trev.) Meisn, a traditional Chinese medicine with anti-tumor effect, a novel isoflavone reductase-like gene, FcIRL, was cloned using RACE strategy from a cDNA library of high flavonoids-producing callus. The full-length cDNA of the FcIRL was 1 217 bp (accession no. EU116032), which contained a 942 bp open reading frame (ORF) encoding a 313 amino acid protein. Two stop codons (TAG) and a putative polyadenylation signal ATAAA at 24 bp upstream from the polyadenylation site was found in 5' and 3' UTR, separately. And no intron was found in the genomic sequence yet. FcIRL contained a predicted N-terminal acetylation site (M1-K5) and a NADPH-binding motif (G10-G-T-G13-Y-I-G16) in the N-terminal region, a conserved NmrA (nitrogen metabolite repression regulator) domain (V6-N244), multi-phosphorylation sites and one conserved N-glycosylation site (N214). Sequence homology comparison, phylogenetic analysis and advanced structures prediction all suggested that FcIRL belonged to the class of pinoresinol-lariciresinol reductase (PLR), which is a key enzyme in synthetic pathway of 8-8'-linked lignans, with function in catalyzing reduction of pinoresinol and lariciresinol into secoisolariciresinol, and medicinal secondary metabolism and resistance in F. cymosum.
Amino Acid Sequence ; Base Sequence ; Cloning, Molecular ; Fagopyrum ; enzymology ; genetics ; Flavonoids ; genetics ; Lignans ; metabolism ; Molecular Sequence Data ; Oxidoreductases ; genetics ; Oxidoreductases Acting on CH-CH Group Donors ; genetics ; Protein Structure, Tertiary ; Sequence Homology, Amino Acid

OBJECTIVETo study the effect of Guanxin No. 2 (GX2) on gene variant expression profile in rats after myocardial infarction (MI).

METHODSSix SD rats were equally randomized into the sham operated group, the model group and the GX2 group, and they received gastric perfusion with water and GX2 (10 g/kg) respectively. MI model was established by ligating the left-anterior descending branch of coronary artery after 10 days of perfusion, and rats' myocardial tissue in the junction zone was assessed 24 h later for gene chip detection with DNA microarray. Then a cluster analysis was conducted, and the different expressions of key genes were verified by real-time reverse transcription-polymerase chain reaction.

RESULTSThe up-regulating gene expressions in myocardial tissue in the junction zone increased after ischemia. After GX2 intervention, the up- or down-regulating gene expressions, especially the 2 genes, all-trans-13,14-dihydroretinol saturase (AF465614) and similar to expressed sequence AW413625 (AA799328) decreased significantly. In the common genes, more genes involving activity of signal transducer presented in the model group and the GX2 group and those in the latter showed a certain specificity.

CONCLUSIONGX2 could improve the characteristics of variant gene expression profile in MI rats to a certain extent.

Animals ; Drugs, Chinese Herbal ; pharmacology ; Gene Expression ; drug effects ; Gene Expression Profiling ; Myocardial Ischemia ; genetics ; metabolism ; Myocardium ; metabolism ; Oxidoreductases Acting on CH-CH Group Donors ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo analyze the impact of depletion of the twin arginine translocation (TAT) system on virulence and physiology of Yersinia enterocolitica for a better understanding of its pathogenicity.

METHODSWe constructed a DeltatatC::SpR mutant of Yersinia enterocolitica by P1 phage mediated transduction using Escherichia coli K-12 DeltatatC::SpR strain as a donor.

RESULTSA P1-mediated genetic material transfer was found between the two species of enterobacteria, indicating a great potential of acquisition of antibiotic resistance in emergency of a new threatening pathogen by genetic material exchanges. Periplasmic trimethylamine N-oxidase reductase activity was detected in the wild type Y. enterocolitica strain and translocation of this enzyme was completely abolished by the DeltatatC::SpR mutation. In addition, the DeltatatC::SpR mutation showed a pleiotropic effect on the metabolism of Y. enterocolitica. However, the tat mutation did not seem to affect the mobility and virulence of Y. enterocolitica under the conditions used.

CONCLUSIONUnlike other pathogenic bacteria studied, the TAT system of Y. enterocolitica might play an important role in the pathogenic process, which is distinct from other pathogens, such as Pseudomonas aeruginosa and enterohemorrhagic E. coli O157:H7.

Drug Resistance, Microbial ; genetics ; Genes, Bacterial ; Mutation ; Oxidoreductases Acting on CH-NH Group Donors ; metabolism ; Transduction, Genetic ; Virulence ; Yersinia enterocolitica ; enzymology ; genetics ; metabolism ; pathogenicity