Biochemistry

Glycolysis enzymes are located in the cytosol of cells.  Pyruvate enters the mitochondrion to be metabolized further Mitochondrial compartments: The mitochondrial matrix contains Pyruvate Dehydrogenase and enzymes of Krebs Cycle, plus other pathways such as fatty acid oxidation.  Pyruvate Dehydrogenase catalyzes oxidative decarboxylation of pyruvate, to form acetyl-CoA FAD (Flavin Adenine Dinucleotide) is a derivative of the B-vitamin riboflav…

Glycogen Metabolism The formation of glycogen from glucose is called Glycogenesis   Glycogen is a polymer of glucose residues linked mainly by a(1→ 4)  glycosidic linkages. There are a(1→6) linkages at branch points. The chains and branches are longer than shown. Glucose is stored as glycogen predominantly in liver and muscle cells Glycogen Synthesis Uridine diphosphate glucose (UDP-glucose) is the immediate precursor for glycogen…

FAT-SOLUBLE VITAMINS The fat-soluble vitamins, A, D, E, and K, are stored in the body for long periods of time and generally pose a greater risk for toxicity when consumed in excess than water-soluble vitamins. VITAMIN A: RETINOL  Vitamin A, also called retinol, has many functions in the body. In addition to helping the eyes adjust to light changes, vitamin A plays an important role in bone growth, tooth development, reproduction, cell division, gene e…

PHOSPHOLIPIDS These are complex or compound lipids containing phosphoric acid, in addition to fatty acids, nitrogenous base and alcohol  There are two  classes of phospholipids 1. Glycerophospholipids (or phosphoglycerides) that contain glycerol as the alcohol. 2. Sphingophospholipids (or sphingomyelins) that contain sphingosine as the alcohol Glycerophospholipids Glycerophospholipids are the major lipids that occur in biological membran…

Glycogenolysis Breakdown of  glycogen to glucose is called glycogenolysis. The Breakdown of glycogen takes place in liver and muscle. In Liver , the end product of glycodgen breakdown is glucose where as in muscles the end product is Lactic acid Under the combined action of Phosphorylase  (breaks only –α-(1,4) linkage )and Debranching enzymes (breaks only α-(1,6) linkage )glycogen is broken down to glucose.…