“Discover how essential vitamins like B2, B3, B6, B12, folate, and others impact fatty acid, triglyceride, and nucleotide metabolism. This detailed overview explains impaired reactions, enzymes affected, and consequences of deficiencies.”
Overview of Fatty Acid Metabolism Disorders Disorder Enzyme Defect Impairment Type Clinical Manifestations Mnemonic Medium-Chain Acyl-CoA Dehydrogenase Deficiency (MCAD) Acyl-CoA Dehydrogenase specific for medium-chain fatty acids Impaired beta-oxidation of medium-chain fatty acids Hypoglycemia, lethargy, vomiting, seizures, coma, and sudden infant death MCAD = “Might Collapse And Die” Carnitine Deficiency Carnitine transporter or synthesis defect
Disoder Enzyme Defect Impairment Type Clinical Manifestations Mnemonic Carnitine Deficiency Carnitine transporter or synthesis defect Impaired transport of long-chain fatty acids Muscle weakness, cardiomyopathy, hypoketotic hypoglycemia “Car Can’t Fuel” CPT I Deficiency CPT I (Carnitine Palmitoyltransferase I) Impaired long-chain fatty acid entry into mitochondria Hypoketotic hypoglycemia, liver dysfunction, hyperammonemia “CPT I = Can’t Properly
Table 1: Role of organelles in Fatty Acid Synthesis, Elongation, and Desaturation Process Organelle Function Key Enzymes/Features De Novo Fatty Acid Synthesis Cytoplasm Formation of palmitate (16-carbon saturated fatty acid) from acetyl-CoA and malonyl-CoA. Acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS) Elongation of Fatty Acids Endoplasmic Reticulum (ER), Mitochondria Extends the carbon chain of long-chain
Clinical Case: A 6-year-old boy presents to the emergency department with episodes of severe muscle weakness, fatigue, and dark-colored urine after prolonged physical activity. His parents report that he often becomes weak during periods of fasting or intense exercise. Blood tests reveal elevated levels of fatty acylcarnitine and normal levels of free carnitine. Plasma analysis
Biosynthesis of cholesterol The biosynthesis of cholesterol may be divided into five steps: (1) Synthesis of Mevalonate from acetyl-CoA. (2) Formation of Isoprenoid units from Mevalonate by loss of CO2. (3) Condensation of six isoprenoid units forms Squalene. (4) The cyclization of Squalene gives rise to the parent steroid, Lanosterol. (5)Formation of cholesterol from lanosterol.
Biosynthesis of cholesterol- a quick revision Read More »
Enzyme and pathway Effect of substrate concentration Allosteric Modification/ Feedback Inhibition/Covalent modification Induction/ Repression Clinical Significance Acetyl CoA Carboxylase (Fatty acid synthesis) Activity increases during the well-fed state Activity decreases during fasting Activator- Citrate, ATP Acetyl CoA Insulin- activates the enzyme by covalent modification of the enzyme (dephosphorylation through stimulating protein phosphatase enzyme) Inhibitors– Long-chain fatty
Regulatory Mechanisms- Lipid Metabolism (summary Chart) Read More »
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,
Fatty Acid Synthesis- Lecture-1 (Quick revision) Read More »
