Citrate Synthase: Difference between revisions
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==The Structure and Mechanism of Citrate Synthase== | ==The Structure and Mechanism of Citrate Synthase== | ||
<applet load='2cts' size='300' color='white' frame='true' align='right' caption='Citrate Synthase Closed Form' name='closed'/> <applet load='1cts' size='300' color='white' frame='true' align='right' caption='Citrate Synthase Open Form' name='open'/> | <applet load='2cts' size='300' color='white' frame='true' align='right' caption='Citrate Synthase Closed Form' name='closed'/> <applet load='1cts' size='300' color='white' frame='true' align='right' caption='Citrate Synthase Open Form' name='open'/> | ||
Citrate synthase is an enzyme active in the mitochondria, where it is responsible for catalyzing the first reaction of the citric acid cycle (Krebs Cycle): the condensation of acetyl-CoA and oxaloacetate to form citrate. Although it is a mitochondrial enzyme (in fact, it is often used as a quantitative enzyme marker for intact mitochondria), it is encoded by nuclear DNA, not mitochondrial <ref>"Citrate Synthase -." Wikipedia, the Free Encyclopedia. Web. 22 Mar. 2010. <http://en.wikipedia.org/wiki/Citrate_synthase></ref>. The standard free energy change (ΔG°’) for the citrate synthase reaction is -31.5kJ/mol <ref name="voet">Voet, Donald, Judith G. Voet, and Charlotte W. Pratt. Fundamentals of Biochemistry: Life at the Molecular Level. Hoboken, NJ: Wiley, 2008.</ref>. This negative free energy value means that citrate synthase is likely to function far from equilibrium under physiological conditions, and is thus a rate-determining enzyme in the citric acid cycle. | Citrate synthase is an enzyme active in the mitochondria, where it is responsible for catalyzing the first reaction of the citric acid cycle (Krebs Cycle): the condensation of acetyl-CoA and oxaloacetate to form citrate. Although it is a mitochondrial enzyme (in fact, it is often used as a quantitative enzyme marker for intact mitochondria), it is encoded by nuclear DNA, not mitochondrial <ref>"Citrate Synthase -." Wikipedia, the Free Encyclopedia. Web. 22 Mar. 2010. <http://en.wikipedia.org/wiki/Citrate_synthase></ref>. The standard free energy change (ΔG°’) for the citrate synthase reaction is -31.5kJ/mol <ref name="voet">Voet, Donald, Judith G. Voet, and Charlotte W. Pratt. Fundamentals of Biochemistry: Life at the Molecular Level. Hoboken, NJ: Wiley, 2008.</ref>. This negative free energy value means that citrate synthase is likely to function far from equilibrium under physiological conditions, and is thus a rate-determining enzyme in the citric acid cycle. | ||
'''Structure:''' Citrate synthase is a single amino acid chain <scene name='Daniel_Eddelman_Sandbox_2/Cts_open_monomer/1'>monomer</scene>. Biologically, however, it exists as a | '''Structure:''' Citrate synthase is a single amino acid chain <scene name='Daniel_Eddelman_Sandbox_2/Cts_open_monomer/1'>monomer</scene>. Biologically, however, it exists as a | ||
