Hans krebs proposed the citric acid cycle for the complete oxidation of pyruvate in animal tissues in 1937 (he wrongly hypothesized that pyruvate condenses with oxaloacetate in his original proposal) The citric acid cycle was confirmed to be universal in cells by in vitro studies with purified enzymes and in vivo studies with radio isotopes( radio isotope tracer experiments Krebs was awarded the Nobel prize in medicine in 1953 for revealing the citric acid cycle(thus also called the Krebs cycle
• Hans Krebs proposed the “citric acid cycle” for the complete oxidation of pyruvate in animal tissues in 1937 (he wrongly hypothesized that pyruvate condenses with oxaloacetate in his original proposal). • The citric acid cycle was confirmed to be universal in cells by in vitro studies with purified enzymes and in vivo studies with radio isotopes (“radio isotope tracer experiments”). • Krebs was awarded the Nobel prize in medicine in 1953 for revealing the citric acid cycle (thus also called the Krebs cycle)
The Nobel Prize in Physiology or Medicine 1953 Pr ation Speech for his discovery of the citric acid cycle Sir hans adolf Krebs Great britain Sheffield University Sheffield, Great Britain 1900-1981 Biography
4. The acetyl group (carried by CoA) is completely oxidized to CO, via the citric acid cycle The4 carbon oxaloacetate(草酰乙酸) acts as the carrier> for the oxidation. The two carbons released as 2 co in the first cycle of oxidation are not from the acetyl-CoA just oined The 8 electrons released are collected by three NAD and one FaD One molecule of ATP (or GTP)is produced per cycle by substrate-level phosphorylation
4. The acetyl group (carried by CoA) is completely oxidized to CO2 via the citric acid cycle • The 4-carbon oxaloacetate (草酰乙酸) acts as the “carrier” for the oxidation. • The two carbons released as 2 CO2 in the first cycle of oxidation are not from the acetyl-CoA just joined. • The 8 electrons released are collected by three NAD+ and one FAD. • One molecule of ATP (or GTP) is produced per cycle by substrate-level phosphorylation
C 6 NADH NADH CO FADH 2 5 nadh GTP C co2
Acetyl-CoA CHeC-SCoA H-O CoA-SH The citric O=C-C HO-C--CO0 CHy-Coo Dehydration ac cid cycle Dehydrogenation Oxaloacetate Citrate H,O COO 10--CH Ho-co0 C-co0 CoO ⑦ Hydration NADH H O Fumarate H-C-COo FADE HO-C-COO CoO Oxidative CHa-coo C CHa-coo C-COo COA-SH - Ketoglutarate C-S-CoA CoA-SH GDP o ADP) SuccinyL-CoA Substrate level Oxidative
The citric acid cycle