Thermostable anthranilate synthase from the marine sulfate-reducing hyperthermophile Archaeoglobus fulgidus has been expressed in Escherichia coli, purified, and characterized. The functional enzyme is an alpha2beta2 heterotetrameric complex of molecular mass 150+/-15 kDa. It is composed of two TrpE (50 kDa) and two TrpG (18 kDa) subunits. The extrinsic factors glycerol (25%) and potassium chloride (2 M) stabilized the recombinant enzyme against thermal inactivation. In the presence of these extrinsic factors, the enzyme was highly thermostable, exhibiting a half-life of thermal inactivation of about 1 h at 85 degrees C. The kinetic constants for the enzyme under these conditions were: Km (chorismate) 84 microM, Km (glutamine) 7.0 mM, kcat 0.25 s(-1), and pH optimum 8.0. The enzyme was competitively, though non-cooperatively, inhibited by tryptophan.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1007/s00792-004-0406-3 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Geochemical signatures and nanomechanical properties of echinoid tests from nearshore habitats of Florida: environmental and physiological controls on echinoid biomineralization.
PeerJ
January 2025
Florida Museum of Natural History, University of Florida, Gainesville, FL, United States of America.
The mechanisms that regulate minor and trace element biomineralization in the echinoid skeleton can be primarily controlled biologically (, by the organism and its vital effects) or by extrinsic environmental factors. Assessing the relative role of those controls is essential for understanding echinoid biomineralization, taphonomy, diagenesis, and their potential as geochemical archives. In this study, we (1) contrast geochemical signatures of specimens collected across multiple taxa and environmental settings to assess the effects of environmental and physiological factors on skeletal biomineralogy; and (2) analyze the nanomechanical properties of the echinoid skeleton to assess potential linkages between magnesium/calcium (Mg/Ca) ratios and skeletal nanohardness.
View Article and Find Full Text PDFPhysiology of bridging stent grafts after fenestrated/branched endovascular aortic repair: Where translational science meets the clinical profile.
Exp Physiol
January 2025
Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK.
Fenestrated/branched endovascular aortic repair emerges as the primary therapeutic modality for intricate aortic pathologies encompassing the paravisceral and thoracoabdominal segments, where bridging stent grafts (BSGs) play a vital role in linking the primary aortic endograft with target vessels. Bridging stent grafts can be categorized mainly into self-expanding stent grafts (SESGs) and balloon-expandable stent grafts (BESGs). Physiological factors significantly influence post-complex endovascular aortic repair BSG behaviour, impacting clinical outcomes of SESGs and BESGs in different but overlapping ways.
View Article and Find Full Text PDFComparative Analysis of 4NQO- and Ethanol-Induced Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma in Male and Female Mice: Association With Peripheral Blood Inflammatory Markers.
J Oral Pathol Med
January 2025
Department of Oral and Maxillofacial Pathology, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil.
Background: Considering that peripheral blood biomarkers are prognostic predictors for several human tumors, this study aimed to comparatively analyze the association of hematological alterations with the incidence of epithelial dysplasia (ED) and oral squamous cell carcinoma (OSCC) in male and female mice treated with 4-nitroquinoline-N-oxide (4NQO) and ethanol (EtOH).
Methods: 120 C57Bl/6J mice (60 males and 60 females) were allocated to four groups (n = 15). They were treated firstly either with 5 mg/mL propylene glycol (PPG) or 100 μg/mL 4NQO in the drinking water for 10 weeks, followed by sterilized water (HO) or 8% EtOH (v/v) for 15 weeks, as follows: PPG/HO, PPG/EtOH, 4NQO/HO, and 4NQO/EtOH (CEUA-UFU, #020/21).
Meiosis and retinoic acid in the mouse fetal gonads: An unforeseen twist.
Curr Top Dev Biol
January 2025
Université de Strasbourg, IGBMC UMR 7104, Illkirch, France; CNRS, UMR 7104, Illkirch, France; Inserm, UMR-S 1258, Illkirch, France; IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France. Electronic address:
In mammals, differentiation of germ cells is crucial for sexual reproduction, involving complex signaling pathways and environmental cues defined by the somatic cells of the gonads. This review examines the long-standing model positing that all-trans retinoic acid (ATRA) acts as a meiosis-inducing substance (MIS) in the fetal ovary by inducing expression of STRA8 in female germ cells, while CYP26B1 serves as a meiosis-preventing substance (MPS) in the fetal testis by degrading ATRA and preventing STRA8 expression in the male germ cells until postnatal development. Recent genetic studies in the mouse challenge this paradigm, revealing that meiosis initiation in female germ cells can occur independently of ATRA signaling, with key roles played by other intrinsic factors like DAZL and DMRT1, and extrinsic signals such as BMPs and vitamin C.
View Article and Find Full Text PDFStarch retrogradation in starch-based foods: Mechanisms, influencing factors, and mitigation strategies.
Int J Biol Macromol
January 2025
Institute of Spice and Beverage Research, Chinese Academy of Tropical Agricultural Sciences, Wanning 571533, China; Key Laboratory of Processing Suitability and Quality Control of the Special Tropical Crops of Hainan Province, Hainan 571533, China; Sanya Research Academy, Chinese Academy of Tropical Agriculture Science, Sanya 572019, China. Electronic address:
Starch-based foods are the most common foods in the daily diets. However, starch-based foods are prone to starch retrogradation, resulting in texture hardening, taste deterioration and nutrient loss. This paper reviewed the mechanisms and the influencing factors of starch retrogradation in starch-based foods, and the strategies to mitigate it.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!