Search results for "Dioxygenase"
showing 10 items of 66 documents
Role of reactive oxygen species in the regulation of HIF-1 by prolyl hydroxylase 2 under mild hypoxia
2012
The function and survival of eukaryotic cells depends on a constant and sufficient oxygen supply. Cells recognize and respond to hypoxia by accumulation of the transcription factor hypoxia-inducible factor 1 (HIF-1), composed of an oxygen-sensitive HIF-1α and a constitutive HIF-1β subunit. Besides physiology, HIF-1 induction is involved in major pathological processes such as cardiovascular disease, inflammation and cancer, which are associated with the formation of reactive oxygen species (ROS). ROS have been reported to affect HIF-1 activity but the role for ROS in regulating HIF-1 has not been definitely settled. In order to shed light on the redox-regulation of HIF-1 by ROS, we studied …
Estimation of the density of the protocatechuate-degrading bacterial community in soil by real-time PCR
2008
Summary The β-ketoadipate pathway is the major route for degradation of aromatic compounds by various soil microorganisms. Protocatechuate 3,4-dioxygenase, a key enzyme of this pathway and which is encoded by pcaGH genes, catalyses the ring cleavage of protocatechuate. Microorganisms harbouring pcaGH genes are widely distributed in the environment but little is known about their relative abundance within the total microflora. Hence, this paper reports the development of a real-time PCR assay to quantify the bacterial pcaH sequence that encodes the β sub-unit of the protocatechuate 3,4-dioxygenase. This real-time PCR assay was linear over seven orders of magnitude with a calculated efficienc…
A vertebrate globin expressed in the brain.
2000
Haemoglobins and myoglobins constitute related protein families that function in oxygen transport and storage in humans and other vertebrates. Here we report the identification of a third globin type in man and mouse. This protein is predominantly expressed in the brain, and therefore we have called it neuroglobin. Mouse neuroglobin is a monomer with a high oxygen affinity (half saturation pressure, P50 approximately 2 torr). Analogous to myoglobin, neuroglobin may increase the availability of oxygen to brain tissue. The human neuroglobin gene (NGB), located on chromosome 14q24, has a unique exon-intron structure. Neuroglobin represents a distinct protein family that diverged early in metaz…
Loss of PHD3 allows tumours to overcome hypoxic growth inhibition and sustain proliferation through EGFR
2014
Solid tumours are exposed to microenvironmental factors such as hypoxia that normally inhibit cell growth. However, tumour cells are capable of counteracting these signals through mechanisms that are largely unknown. Here we show that the prolyl hydroxylase PHD3 restrains tumour growth in response to microenvironmental cues through the control of EGFR. PHD3 silencing in human gliomas or genetic deletion in a murine high-grade astrocytoma model markedly promotes tumour growth and the ability of tumours to continue growing under unfavourable conditions. The growth-suppressive function of PHD3 is independent of the established PHD3 targets HIF and NF-κB and its hydroxylase activity. Instead, l…
Increased activities of prolyl 4-hydroxylase and galactosylhydroxylysyl glucosyltransferase, enzymes of collagen biosynthesis, in skeletal muscle of …
1983
The activities of prolyl 4-hydroxylase (PH) and galactosylhydroxylysyl glucosyltransferase (GGT), and the concentration of 4-hydroxyproline were measured in red and white parts of quadriceps femoris muscle of mice after 3, 10, and 20 sessions of daily endurance training. The activities of PH and GGT increased in the red part of the muscle after training for 3 and 10 times and returned to the control level after 20 training sessions. In the white muscle the increase of PH activity was less than in the red muscle. No alteration in GGT activity was observed in the white muscle. The concentration of hydroxyproline was unchanged in the both types of skeletal muscle. The results suggest that coll…
Subcellular localization and purification of a p-hydroxyphenylpyruvate dioxygenase from cultured carrot cells and characterization of the correspondi…
1997
p-Hydroxyphenylpyruvate dioxygenase catalyses the transformation of p-hydroxyphenylpyruvate into homogentisate. In plants this enzyme has a crucial role because homogentisate is the aromatic precursor of all prenylquinones. Furthermore this enzyme was recently identified as the molecular target for new families of potent herbicides. In this study we examine precisely the localization of p-hydroxyphenylpyruvate dioxygenase activity within carrot cells. Our results provide evidence that, in cultured carrot cells, p-hydroxyphenylpyruvate dioxygenase is associated with the cytosol. Purification and SDS/PAGE analysis of this enzyme revealed that its activity is associated with a polypeptide of 4…
Identification of a novel recurrent 1q42.2-1qter deletion in high risk MYCN single copy 11q deleted neuroblastomas
2012
Neuroblastoma is an aggressive embryonal tumor that accounts for similar to 15% of childhood cancer deaths. Hitherto, despite the availability of comprehensive genomic data on DNA copy number changes in neuroblastoma, relatively little is known about the genes driving neuroblastoma tumorigenesis. In this study, high resolution array comparative genome hybridization (CGH) was performed on 188 primary neuroblastoma tumors and 33 neuroblastoma cell lines to search for previously undetected recurrent DNA copy number gains and losses. A new recurrent distal chromosome 1q deletion (del(1)(q42.2qter)) was detected in seven cases. Further analysis of available array CGH datasets revealed 13 additio…
Increased mRNAs for procollagens and key regulating enzymes in rat skeletal muscle following downhill running.
1999
The purpose of the study was to investigate pre-translational regulation of collagen expression after a single bout of exercise. We analysed steady-state messenger ribonucleic acid (mRNA) levels for collagen types I, III and IV, alpha- and beta-subunits of prolyl 4-hydroxylase and lysyl oxidase (enzymes modifying procollagen chains), and enzyme activity of prolyl 4-hydroxylase from rat soleus muscle (MS) and the red parts of quadriceps femoris muscle (MQF) after 12 h and after 1, 2, 4, 7 and 14 days of downhill (-13.5 degrees ) treadmill running at a speed of 17 m.min-1 for 130 min. Histological and biochemical assays revealed exercise-induced muscle damage in MQF but not MS. Steady-state m…
PHD3 regulates EGFR internalization and signalling in tumours
2014
Tumours exploit their hypoxic microenvironment to induce a more aggressive phenotype, while curtailing the growth-inhibitory effects of hypoxia through mechanisms that are poorly understood. The prolyl hydroxylase PHD3 is regulated by hypoxia and plays an important role in tumour progression. Here we identify PHD3 as a central regulator of epidermal growth factor receptor (EGFR) activity through the control of EGFR internalization to restrain tumour growth. PHD3 controls EGFR activity by acting as a scaffolding protein that associates with the endocytic adaptor Eps15 and promotes the internalization of EGFR. In consequence, loss of PHD3 in tumour cells suppresses EGFR internalization and hy…
Genome-wide analysis reveals DNA methylation markers that vary with both age and obesity
2014
AbstractThe combination of the obesity epidemic and an aging population presents growing challenges for the healthcare system. Obesity and aging are major risk factors for a diverse number of diseases and it is of importance to understand their interaction and the underlying molecular mechanisms. Herein the authors examined the methylation levels of 27578 CpG sites in 46 samples from adult peripheral blood. The effect of obesity and aging was ascertained with general linear models. More than one hundred probes were correlated to aging, nine of which belonged to the KEGG group map04080. Additionally, 10 CpG sites had diverse methylation profiles in obese and lean individuals, one of which wa…