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Structure and Biosynthesis of Lignin
Published in Jean-Luc Wertz, Magali Deleu, Séverine Coppée, Aurore Richel, Hemicelluloses and Lignin in Biorefineries, 2017
Jean-Luc Wertz, Magali Deleu, Séverine Coppée, Aurore Richel
In plants, chorismate is a common precursor of at least four branches of metabolic pathways leading to the formation of Trp, Phe/Tyr, salicylate/phylloquinone, and folate.10 Four enzymes catalyze the committed step of the respective pathways and compete for chorismate. The Trp pathway converts chorismate to Trp via six enzymatic reactions. In contrast to the Trp pathway, the knowledge of the plant Phe and Tyr pathways is still in its infancy. In the first step of the pathways, chorismate is converted by chorismate mutase (CM) to prephenate, of which subsequent conversion to Phe and Tyr may occur via two alternative pathways. In one route (the arogenate pathway), prephenate is first transaminated to L-arogenate followed by dehydration/decarboxylation to Phe or dehydrogenation/decarboxylation to Tyr. In the other route (the phenylpyruvate or 4-hydroxyphenylpyruvate pathway), these reactions occur in reverse order. Recent genetic evidence indicates that the arogenate pathway is the predominant route for Phe biosynthesis in plants.
Synthesis and evaluation of antimicrobial, antitubercular and anticancer activities of benzimidazole derivatives
Published in Egyptian Journal of Basic and Applied Sciences, 2018
Snehlata Yadav, Balasubramanian Narasimhan, Siong Meng Lim, Kalavathy Ramasamy, Mani Vasudevan, Syed Adnan Ali Shah, Abhishek Mathur
Tuberculosis (TB), caused by Mycobacterium tuberculosis (M. tuberculosis), remains a pivotal cause of high mortality worldwide despite the handiness of highly potent antitubercular drugs due to the development of resistance by the mycobacterium as a result of gene mutation to first-line antitubercular drugs [5]. To combat the mycobacterial resistance, there is a need to identify novel targets unique to M. tuberculosis which are absent in humans whose blockage would either prove lethal to the bacterium or render it extremely susceptible to the host immune response [6]. Chorismate mutase (CM), isocitrate lyase (ICL), and pantothenate synthetase (PS) are few such unique targets for M. tuberculosis [7]. Chorismate is a precursor of important molecules such folic acid, menaquinones, mycobactins and aromatic amino acids. The shikimate pathway utilizes CM as one of the key enzymes for catalyzing the isomerization of chorismate to prephenate for biosynthesis of l-phenylalanine and l-tyrosine in the mycobacteria [8,9] . The glyoxylate metabolism shunt employs ICL as an important enzyme in the main metabolic route for the biosynthesis of cellular material i.e., fatty acids, which might be the major source of carbon for M. tuberculosis during growth on C2 substances [10]. PS catalyzes the condensation of pantothenate from D-pantoate and β-alanine for the biosynthesis of coenzyme A and acyl carrier protein in mycobacterium [11].