Diversity and Common Principles in Enzymatic Activation of Hydrocarbons

2012 ◽  
Keyword(s):  
Enzymatic Activation ◽  
Activation Of Hydrocarbons

scholarly journals An enzymatic activation of formaldehyde for nucleotide methylation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Charles Bou-Nader ◽  
Frederick W. Stull ◽  
Ludovic Pecqueur ◽  
Philippe Simon ◽  
Vincent Guérineau ◽  
...  
Keyword(s):  
Amino Acids ◽  
Thymidylate Synthase ◽  
Active Site ◽  
De Novo ◽  
Crystallographic Structure ◽  
De Novo Synthesis ◽  
Active Site Residues ◽  
Enzymatic Activation ◽  
Enzyme Cofactors ◽  
Unique Ability

AbstractFolate enzyme cofactors and their derivatives have the unique ability to provide a single carbon unit at different oxidation levels for the de novo synthesis of amino-acids, purines, or thymidylate, an essential DNA nucleotide. How these cofactors mediate methylene transfer is not fully settled yet, particularly with regard to how the methylene is transferred to the methylene acceptor. Here, we uncovered that the bacterial thymidylate synthase ThyX, which relies on both folate and flavin for activity, can also use a formaldehyde-shunt to directly synthesize thymidylate. Combining biochemical, spectroscopic and anaerobic crystallographic analyses, we showed that formaldehyde reacts with the reduced flavin coenzyme to form a carbinolamine intermediate used by ThyX for dUMP methylation. The crystallographic structure of this intermediate reveals how ThyX activates formaldehyde and uses it, with the assistance of active site residues, to methylate dUMP. Our results reveal that carbinolamine species promote methylene transfer and suggest that the use of a CH2O-shunt may be relevant in several other important folate-dependent reactions.

Wound Closure in the Invasive Green AlgaCaulerpa taxifolia by Enzymatic Activation of a Protein Cross-Linker

2005 ◽  
Vol 44 (18) ◽  
pp. 2806-2808 ◽  
Author(s):  
Sven Adolph ◽  
Verena Jung ◽  
Janine Rattke ◽  
Georg Pohnert
Keyword(s):  
Wound Closure ◽  
Enzymatic Activation ◽  
Cross Linker

scholarly journals Remodeling of Cancer-Specific Metabolism under Hypoxia with Lactate Calcium Salt in Human Colorectal Cancer Cells

Cancers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1518
Author(s):  
Keun-Yeong Jeong ◽  
Jae-Jun Sim ◽  
Min Hee Park ◽  
Hwan Mook Kim
Keyword(s):  
Colorectal Cancer ◽  
Intracellular Calcium ◽  
Cancer Cells ◽  
Calcium Salt ◽  
Lactate Production ◽  
Tca Cycle ◽  
Anaerobic Glycolysis ◽  
Human Colorectal Cancer ◽  
Antitumor Effects ◽  
Enzymatic Activation

Hypoxic cancer cells meet their growing energy requirements by upregulating glycolysis, resulting in increased glucose consumption and lactate production. Herein, we used a unique approach to change in anaerobic glycolysis of cancer cells by lactate calcium salt (CaLac). Human colorectal cancer (CRC) cells were used for the study. Intracellular calcium and lactate influx was confirmed following 2.5 mM CaLac treatment. The enzymatic activation of lactate dehydrogenase B (LDHB) and pyruvate dehydrogenase (PDH) through substrate reaction of CaLac was investigated. Changes in the intermediates of the tricarboxylic acid (TCA) cycle were confirmed. The cell viability assay, tube formation, and wound-healing assay were performed as well as the confirmation of the expression of hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF). In vivo antitumor effects were evaluated using heterotopic and metastatic xenograft animal models with 20 mg/kg CaLac administration. Intracellular calcium and lactate levels were increased following CaLac treatment in CRC cells under hypoxia. Then, enzymatic activation of LDHB and PDH were increased. Upon PDH knockdown, α-ketoglutarate levels were similar between CaLac-treated and untreated cells, indicating that TCA cycle restoration was dependent on CaLac-mediated LDHB and PDH reactivation. CaLac-mediated remodeling of cancer-specific anaerobic glycolysis induced destabilization of HIF-1α and a decrease in VEGF expression, leading to the inhibition of the migration of CRC cells. The significant inhibition of CRC growth and liver metastasis by CaLac administration was confirmed. Our study highlights the potential utility of CaLac supplementation in CRC patients who display reduced therapeutic responses to conventional modes owing to the hypoxic tumor microenvironment.

scholarly journals Enzymatic Activation of Biotin

1964 ◽  
Vol 239 (11) ◽  
pp. 3997-4005 ◽  
Author(s):  
James E. Christner ◽  
Milton J. Schlesinger ◽  
Minor J. Coon
Keyword(s):  
Enzymatic Activation
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