Steps of de novo synthesis of cholesterol Cholesterol is derived from diet, de novo synthesis, and the hydrolysis of cholesteryl esters. A little more than half the cholesterol in the body arises by synthesis (about 700 mg/d), and the average diet provides the remainder. The liver and intestine account for approximately 10% each of the […]
Utilization of ketone bodies The ketone bodies are water-soluble and are transported across the inner mitochondrial membrane as well as across the blood-brain barrier and cell membranes. Thus, they can be used as a fuel source by a variety of tissues, including the CNS. They are preferred substrates for aerobic muscle and heart, thus sparing
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Ketogenesis Ketogenesis takes place in the liver using Acetyl CoA as a substrate or a precursor molecule. Enzymes responsible for ketone body formation are associated mainly with the mitochondria. Steps of synthesis-Acetoacetate (the first ketone body) is formed from acetyl CoA in three steps (figure ). 1)Two molecules of acetyl CoA condense to form Acetoacetyl
Ketone bodies Ketone bodies can be regarded as a water-soluble, transportable form of acetyl units. Fatty acids are released by adipose tissue and converted into acetyl units by the liver, which then exports them as ketone bodies. Acetoacetate, D(-3) -hydroxybutyrate (Beta-hydroxybutyrate), and acetone are often referred to as ketone bodies (figure-1). Figure-1- showing the structure
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Fatty acid synthesis takes place in three stages- Initiation, Elongation, and Termination Step-1- Initiation a) Formation of Malonyl CoA The fatty acid synthesis starts with the carboxylation of acetyl-CoA to malonyl-CoA. This irreversible reaction is the committed step in fatty acid synthesis. The synthesis of malonyl-CoA is catalyzed by acetyl-CoA carboxylase, which contains a biotin prosthetic
Fatty Acid Synthesis: Key Steps, Enzymes, and Clinical Relevance Explained Read More »
The fatty acid synthesis starts with the carboxylation of acetyl CoA to malonyl CoA. This irreversible reaction is the committed step in fatty acid synthesis (figure 1). Figure- 1- Showing the formation of Malonyl Co A from Acetyl Co A Bicarbonate as a source of CO2 is required in the initial reaction for the carboxylation
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Case details A 65-year-old man was admitted to the emergency department in an unconscious state. Apparently, he had become increasingly depressed after the death of his younger son two months ago. Previously, before his death, he had been a moderate drinker, but consumption of alcohol had increased markedly over the last few weeks. He had
Sources of Fatty acids Diet Adipolysis de novo synthesis(from precursors)- Carbohydrates, protein, and other molecules obtained from the diet in excess of the body’s need can be converted to fatty acids, which are stored as triglycerides De novo Fatty Acid Synthesis Characteristics An extramitochondrial system synthesizes fatty acids This system is present in many tissues,
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Fatty acids are synthesized in the cytosol, whereas acetyl CoA is formed from pyruvate in mitochondria. Hence, acetyl CoA must be transferred from mitochondria to the cytosol. Mitochondria, however, are not readily permeable to acetyl CoA. Carnitine carries only long-chain fatty acids. The barrier to acetyl CoA is bypassed by citrate, which carries acetyl groups
Omega oxidation of fatty acids Another minor pathway for fatty acid oxidation also involves hydroxylation and occurs in the endoplasmic reticulum of many tissues. In this case, hydroxylation takes place on the methyl carbon at the other end of the molecule from the carboxyl group or on the carbon next to the methyl end. It
Minor pathways of oxidation of fatty acids- Lecture-2 (omega and peroxisomal oxidation) Read More »
