SBI 4U: Metablic Processes KREBS CYCLE Founded by Hans Krebs (biochemist at the Univ. of Sheffield) in 1937. He won the Nobel Prize in 1953 along with Fritz Albert Lipmann who discovered the importance of coenzyme-A. An 8-step process with each step catalyzed by a specific enzyme. It is a cycle because the product of step 8 is the reactant in step 1 (oxaloacetate). Section 1.3

SBI 4U: Metablic Processes KREBS CYCLE The overall chemical equation is: Oxaloacetate + acetyl-coA + ADP + P + 3NAD+ + FAD --> CoA + ATP + 3NADH + 3H+ + FADH2 + 2CO2 + oxaloacetate By the end of the Krebs Cycle, the original glucose molecule is consumed. The six carbon atoms have left as carbon dioxide molecules. All that is preserved are 4ATP (two from glycolysis and two from the Krebs Cycle) and 12 reduced coenzymes: 2 NADH from glycolysis 2 NADH from pyruvate oxidation 6 NADH from the Krebs Cycle and 2 FADH2 from the Krebs Cycle Most of the energy from glucose will be produced in the next stage (ETC) Notice in the figure on page 103 that all the carbons in the original glucose molecule are transformed into carbon dioxide. Section 1.3