BIO-310
BIOCHEMISTRY II
VII. WEEK
LECTURE CONTENTS OF 7TH WEEK
•For most eukaryotic cells, which live in aerobic
conditions and can raise their organic fuels to CO2 and H2O,
• Pyruvate dehydrogenase complex,
• Oxidative decarboxylation,
• Citric acid conversion reactions
• Substrates, enzymes and products,
https://www.google.com/url?sa=i&url=https%3A%2F%2Fmedium.com%2F%40biologynotes%2Fkrebs-citric-acid-cycle- ef1609ad171f&psig=AOvVaw354HrVBW-
6AP7mq1KyKlnd&ust=1589319394570000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCOiM_KPirOkCFQAAAAAdAAA AABAD
https://www.google.com/url?sa=i&url=https%3A%2F%2Fmcb.berkeley.edu%2Flabs%2Fkrantz
%2Fmcb102%2Flect_S2008%2FMCB102-SPRING2008-LECTURE8-
CITRIC_ACID_CYCLE.pdf&psig=AOvVaw0tTJYYewLoE_0soSm78SGh&ust=1589319593586000&source=images
&cd=vfe&ved=0CAIQjRxqFwoTCKCC9orjrOkCFQAAAAAdAAAAABAD
https://www.google.com/url?sa=i&url=https%3A%2F%2Fquizlet.com
%2F109287954%2Ftest&psig=AOvVaw0tTJYYewLoE_0soSm78SGh&ust=1589319593586000&source=images
&cd=vfe&ved=0CAIQjRxqFwoTCKCC9orjrOkCFQAAAAAdAAAAABAg
• Pyruvate, the product of glucose, is converted to acetyl-CoA by pyruvate dehydrogenase complex (KoA-SH, NAD +, TPP, Lipoat, FAD +, E1, E2 and E3),
E1 = Pyruvate dehydrogenase, E2 = Dihydrolipoyl transacylase E3 = Dihydrolipoyl dehydrogenase
• Synthases, synthetases, lyases, ligases,
kinases, phosphorylases, dehydrogenases, phosphatase enzymes are enzymes involved in the citric acid cycle.
•This route allows the production of This route allows the production of reducing agents (retained in electron reducing agents (retained in electron carriers) to transfer the energy stored carriers) to transfer the energy stored in the carbohydrates, oils and in the carbohydrates, oils and
proteins to the formation of ATP.
proteins to the formation of ATP.
• The citric acid cycle is achieved by regulation of the enzymes; citrate synthase, isocitrate
dehydrogenase, alpha-ketoglutarate
dehydrogenase complex involved in irreversible reactions.
• TCA is an amphibolic pathway involved in both catabolic and anabolic processes.
• Syntheses of fatty acids and sterols from citrate, synthesis of glutamate and some amino acids as well as synthesis of purines by alpha- ketoglutarate, synthesis of porphyrine and hem by succinyl-CoA, synthesis of aspartate and pyrimidines over oxalacetate, can be used for some glucogenic amino acids and glucose synthesis via PEP.
• Therefore, the cycle does not slow down by different anaplerotic paths in different tissues to prevent the cycle from slowing down due to declining citric acid cycle products.
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%2F5855941%2F&psig=AOvVaw2e5X_Y98pZ9Gq2Drabu5OX&ust=1589142756247000&source=images&cd=vfe&ved=0CAIQjRxq FwoTCJDDpt_Qp-kCFQAAAAAdAAAAABAy
• Ex. In hepatic and renal tissues, pyruvate carboxylase and oxalacetate, oxalacetate with PEP carboxylase in heart and skeletal muscle, malate with malic enzyme in many cells are formed.
https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.slideserve.com%2Felijah-mcdaniel%2Fanaplerotic-
reactions&psig=AOvVaw2e5X_Y98pZ9Gq2Drabu5OX&ust=1589142756247000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCJD Dpt_Qp-kCFQAAAAAdAAAAABAW
•BIOCHEMICAL FORMULAS
REGARDING THE CITRIC ACID CYCLE WILL BE DISCUSSED AND
ENZYMES AND REACTIONS BE INTRODUCED.
REFERENCES
MAIN : LEHNINGER PRINCIPLES OF BIOCHEMISTRY, DAVID L. NELSON, MICHAEL M.
COX, 5TH EDITION, 2013.
PRİNCİPLES OF BİOCHEMİSTRY, H. R. HORTON, L.
A. MORAN, K. G. SCRİMGEOUR, M. D. PERRY, J.
D. RAWN, PEARSON PRENTİS HALL, 2006.
COLOR ATLAS OF BIOCHEMISTRY, J. KOOLMAN, K. H. ROEHM, GEORG THIEME VERLAG, 2005.
HARPER’S ILLUSTRATED BIOCHEMISTRY, R. K.
MURRAY, D. K. GRANNER, P. A. MAYES, V. W.
RODWELL, LANGE MEDICAL BOOKS/MCGRAW- HILL MEDİCAL PUBLISHING DIVISION, 2003.
BASİC CONCEPTS İN BİOCHEMİSTRY, A STUDENT’S SURVİVAL GUİDE, H. F. GİLBERT, MCGRAW-HİLL HEALTH PROFFESİONS DİVİSİON, 2000.
