University:
Liberty University
Course:
BIOM 500 | Introduction to Biomedical Sciences
Academic year:

2024
Views:

245

Pages:

6
Author:

Sheha A.

Regulation of TCA cycle: It is controlled by respiratory rate which is proportional to the energy consumption level of NAD+. Also stimulates the TCA cycle. Citrate synthase: Inhibited by ATP, NADH, and succinyl CoA. Isocitrate dehydrogenase: Inhibited by ATP and NADH, activated by ADP and calcium. α-ketoglutarate dehydrogenase: Inhibited by NADH and succinyl CoA. ADP is important for TCA cycle: If it is absent, there is no oxidation of NADH and FADH2. Accumulation of NADH and FADH2 inhibits the enzymes of TCA cycle. Role of TCA cycle: It is the energy producing final pathway for the oxidation of glucose and Acetyl CoA formed from fatty acid and amino acid breakdown. It provides citrate for fatty acid synthesis. The intermediates of TCA cycle are used for the synthesis of amino acid and glucose by gluconeogenesis. Citric acid involved in the synthesis as well as breakdown of biological compounds, hence it is called an Amphibolic pathway. TCA cycle also taken part in Gluconeogenesis, Transamination, deamination and Synthesis of fatty acids. Function of TCA cycle: Primary function of TCA cycle is the provision of energy. TCA cycle has amphibolic nature (catabolic and anabolic). a) Catabolic Role TCA cycle is the final metabolic pathway for the production of energy from Acetyl CoA obtained from carbohydrates, lipids and proteins in animals. b) Anabolic Role Starting from intermediates of TCA cycle, a no. of compounds can be produced in the body. c) Heme Synthesis Succinyl CoA is used as a starting material in heme synthesis. d. Synthesis of Aspartate and Glutamate: Oxaloacetate and α-ketoglutarate can be converted to amino acids aspartate and glutamate by transamination process. e. Fatty Acid Synthesis: Citrate can be transported out of mitochondria into cytoplasm where it can give back acetyl CoA and oxaloacetate. Acetyl CoA can be used for the synthesis of fatty acid. f. Glucose Synthesis: Intermediates of TCA cycle can be source for synthesis of glucose.