Analyze Intermediary Metabolic concepts in short form
1. Three compulsory lists that must be at your tips-
· Ketogenic and Glucogenic amino acids.
· Essential and Nonessential amino acids.
· Basic, Acidic, Sulphur containing amino acids.
2. Regulatory Enzymes of pathways e.g.
· Citrate synthesis in citric acid cycle.
· Phosphofructokinase in Glycolysis.
· Pyruvate dehydrogenase in Pyruvate Oxidation.
· Pyruvate Carboxykinase in Gluconeogenesis.
· Glycogen Synthase in Glycogenesis.
· Phosphorylase in Glycogenolysis.
· G6PD in PPP.
· HMG CoA reductase in cholesterol synthesis.
3. Search for ATP estimates e.g.,
· 8 ATP’s per Glucose molecule in Glycolysis under aerobic conditions.
· 30 ATP’s per Pyruvate molecule entering citric acid cycle.
· 129 ATP’s per palmitate undergoing b-oxidation.
4. Look for regulatory molecules and feedback inhibitions e.g.,
· Glucose-6-phosphate inhibition on hexokinase.
· Citrate’s inhibitory effect on phosphofructokinase 1.
· Alanine’s inhibitory effect on Pyruvate kinase.
· Acetyl CoA’s inhibitory effect on Pyruvate dehydrogenase.
· Long chain acyl CoA’s inhibitory effect on Acetyl CoA carboxylase.
5. Look for subcellular organelles where the reactions specifically occur.
· Enzymes of citric acid cycle in mitochondrial matrix.
· Enzymes of Glycolysis in cytosol.
· Enzymes of pentose phosphate pathway in cytosol.
· Enzymes of denovo synthesis of fatty acids in cytosol.
· Enzymes of fatty acid oxidation in mitochondria.
6. Always have a clarity regarding precise role of various lipoproteins.
· HDL is cholesterol scavenger.
· Chylomicrons carry dietary cholesterol.
· VLDL are vehicles of transport of triacylglycerol from the liver to extrahepatic tissues.
7. Vitamins and their role as coenzymes e.g.,
· Thiamine in oxidative decarboxylation.
· Niacin in dehydrogenase reactions.
· Pantothenic acid in CoA.
· Pyridoxal phosphate in muscle phosphorylase.
· Biotin in carboxylase enzymes.
· Vitamin B12 to produce succinyl CoA.
· Folate in transfer of one-carbon units.
8. Products that accumulate in metabolic disorders e.g.,
· Homogenisate in urine of Alkaptonuria patients
· Phenyl acetyl glutamine in phenylketonuria.
· Xanthurenate in Vitamin B6 deficiency.
· Branched chain ketonuria in Mapple syrup urine disease.
9. Check for key enzymes responsible for Metabolic disorders e.g.,
· Glucose-6-phosphates in von Gierkes.
· Hepatic fructokinase in essential fructosuria.
· Galactose-1-phosphate uridyl transferase in Galactosemia.
· Cystathionine-b-synthase in homocystinuria.
10. Where nadh forms, where NADPH forms, where FADH2 forms, where substrate level phosphorylation occurs e.g.,
· FADH2 in succinate dehydrogenase in citric acid cycle.
· NADH in all degradative reactions.
· NADPH in all synthetic reactions.
