BISC300 Chapter Notes - Chapter 12: Uridine Triphosphate, Nucleoside Triphosphate, Nitrate Reductase
27 Nov 2016
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However, some enzymes func in 1 direction only. Many enzymes are used for both catabolic and anabolic processes in pathways that are said to be amphibolic, saving additional materials and energy. These steps require use of separate enzymes: 1 to catalyze anabolic rxn. Use of 2 enzymes allows independent regulation of catabolism and anabolism. Thus catabolic and anabolic are never identical, even though they share many enzymes. End-product regulation generally assumes more importance in anabolic pathways. Many rxns in anabolic pathways are endergonic and will not proceed in direction of biosynthesis. Cells solve this prob by connecting endergonic biosynthetic rxns. to hydrolysis of atp and other nucleoside triphosphates. 2 processes are coupled, free energy made available during nucleoside triphosphate breakdown drives biosynthetic rxn to completion. Catabolism and anabolism can be physically separated. Catabolic and anabolic pathways can be localized into distinct cellular compartments a process called compartmentation. Compartmentation also occurs in bacterial and archaeal cells.
