HBG 9 ( TCA Cycle)

• Metabolic pathways in the body include Pentose phosphate, Nucleic acids (DNA, RNA), Amino acids, Proteins, Glucose, Pyruvate, Acetyl CoA, Glycogen/ CHO, TCA cycle, CO2, FADH2, NADH, ATP, CO2, NADPH, Fatty acids, Aspartate, Urea cycle, Urea, ATP.
• Stage 1 and 2 of the TCA cycle produce reduced electron carriers (FADH2 and NADH).
• Stage 3 of the TCA cycle involves the electron transport chain and oxidative phosphorylation.
• Niacin, B3, is a vitamin deficiency that would affect the TCA cycle activity.
• Vitamin C is the major cofactor in enzymatic regulatory mechanism in TCA cycle.
• Biotin, B7, is a vitamin deficiency that would affect the TCA cycle activity.
• The TCA cycle is the FINAL COMMON PATHWAY for oxidation of CHO, lipid & proteins.
• Pyridoxine, B6, is a vitamin deficiency that would affect the TCA cycle activity.
• Thiamine, B1, is a vitamin deficiency that would affect the TCA cycle activity.
• Riboflavin, B2, is a vitamin deficiency that would affect the TCA cycle activity.
• The TCA cycle produces 1 molecule FADH2, 3 molecules NADH.
• Citrate is the starting substrate for the Kreb's cycle.
• Abdominal clamp is a device used in surgery to control bleeding.
• Conversion of food to ATP involves digestion and absorption, amino acids, glucose, and fatty acids, the TCA cycle, metabolism, acetyl CoA, NADH, FADH2, oxidative phosphorylation, ATP, and heat.
• The TCA cycle is only active with aerobic capacity, it produces three NADH, FADH2, and GTP, and synthesizes CHO, Lipid, and Prot.
• The TCA cycle is the final common pathway in the conversion of food to ATP, it generates reduced coenzymes, and is present in the mitochondrial matrix.
• The TCA cycle has three regulatory enzymes.
• The TCA cycle occurs in the MITOCHONDRIAL MATRIX.
• Reduced coenzymes carry proton (H+) and electron (e-).
• Acetyl CoA, Citrate, Oxaloacetate, a-Ketoglutarate, Fatty acid, Glutamate, Aspartate, Glucose are substrates of the TCA cycle.
• The TCA cycle plays anabolic and catabolic roles.
• The PDH Complex consists of 5 enzymes and 2 coenzymes.
• Pyruvate dehydrogenase (Decarboxylase) (E1) is the first enzyme in the PDH Complex.
• Dihydro lipoyl transacetylase (E2) is the second enzyme in the PDH Complex.
• Dihydro lipoyl dehydrogenase (E3) is the third enzyme in the PDH Complex.
• Thiamine pyrophosphate (TPP) is the fourth enzyme in the PDH Complex.
• Lipoic acid is the fifth enzyme in the PDH Complex.
• Coenzyme A is the sixth enzyme in the PDH Complex.
• FAD is the seventh enzyme in the PDH Complex.
• lactate dehydrogenase
• Acetyl CoA Oxaloacetate a - Ketoglutarate Citrate Synthase Iso - citrate Succinyl CoA ATP, Citrate ATP NADH ADP NAD + Ca 2+ Citrate Isocitrate dehydrogenase a - Ketoglutarate Dehydrogenase complex
• Energy deprivation • brain cells dysfunctions
• Vitamins (B1, B2, B3 and B5) play key role for the cycle
• Respiratory control Supply OXIDIZED COFACTOR by respiratory chain – shows the importance of oxygen
• 3 Enzymes • a - KG dehydrogenase • Dihydrolipoyl trans acetylase • Dihydrolipoyl dehydrogehase
• NAD + Acetyl CoA NADH + H + ATPPyruvate dehydrogenase complex ( PDH complex )PYRUVATE (3C) ACETYL CoA PDH Complex Deficiency Accumulation of Pyruvate • lactic acid acidosis • brain cells dysfunction
• Acetyl CoA (2C) Citrate (6C) Isocitrate (6C) a - Ketoglutarate (5C) Succinyl CoA (4C) Succinate (4C) Fumarate (4C) Malate (4C) Oxaloacetate (4C) Citrate synthase Aconitase Isocitrate dehydrogenase a - Ketoglutarate dehydrogenase Succinyl CoA synthetase Succinate dehydrogenase Fumerase Malate dehydrogenase Pyruvate (3C)
• 5 Coenzymes • TPP (Thiamine) • Lipoate • Coenzyme A ( Pantothenic acid) • FAD (Riboflavin) • NAD (Niacin)
• Mnemonic for TCA substrates: CIK SUSI FANCIES MAKAN OREN
• Genetic defects • Severe form à Neonatal death • Moderate form à Infancy death • Mild form à Ataxia