Chapter 20 Carbohydrate Biosynthesis - OoCities
Pentose phosphate pathway (PPP) is a secondary pathway of glucose metabolism, primary being glycolysis. Glucose enters PPP as glucose 6-phosphate. It occurs in the cytosol of tissues active in fatty acid biosynthesis. Those tissues are liver, mammary and adrenal glands and adipose tissue. There are two phases in the pathway: oxidative and non-oxidative. Glyoxylate cycle is a variant of TCA cycle and occurs in bacteria and plants. Gluconeogenesis is a process of biosynthesis of glucose from simpler non carbohydrate precursors such as oxaloacetate or pyruvate. Glucose is stored in the body in the form of glycogen. Glycogen synthesis takes place in the liver and muscle. Starch and sucrose are synthesized in plants. Lactose is synthesized in lactating mammary glands of animals.
Lehninger Chapter 20: Carbohydrate Biosynthesis
, and (2008)Bioinformatic insights into the biosynthesis of the Group B carbohydrate in Streptococcus agalactiae. Microbiology, 154 (5). pp. 1354-1363. ISSN 1350-0872
Streptococcus agalactiae is a major human and animal pathogen, most notable as a cause of life-threatening disease in neonates. S. agalactiae is also called the Group B Streptococcus in reference to the diagnostically significant Lancefield Group B typing antigen. Although the structure of this complex carbohydrate antigen has been solved, little is known of its biosynthesis beyond the identification of a relevant locus in sequenced S. agalactiae genomes. Analysis of the sugar linkages present in the Group B carbohydrate (GBC) structure has allowed us to deduce the minimum enzymology required to complete its biosynthesis. Most of the enzymes required to complete this biosynthesis can be identified within the putative biosynthetic locus. Surprisingly, however, three crucial N-acetylglucosamine transferases and enzymes required for activated precursor synthesis are not apparently located in this locus. A model for GBC biosynthesis wherein the complete polymer is assembled at the cytoplasmic face of the plasma membrane before translocation to the cell surface is proposed. These analyses also suggest that GBC is the major teichoic acid-like polymer in the cell wall of S. agalactiae, whereas lipoteichoic acid is the dominant poly(glycerophosphate) antigen. Genomic analysis has allowed us to predict the pathway leading to the biosynthesis of GBC of S. agalactiae.
Carbohydrate Biosynthesis I: Glycogen Synthesis - …
Gluconeogenesis is a process of biosynthesis of glucose from simpler non carbohydrate precursors such as oxaloacetate or pyruvate. It is a universal pathway in animals, plants, microbes and fungi. It converts pyruvate to glucose (reverse of glycolysis). The irreversible steps of glycolysis are circumvented by four key enzymes of gluconeogenesis. They are pyruvate carboxylase, phosphoenol pyruvate carboxy kinase, fructose-1, 6-bisphosphatase and glucose-6-phosphatase.
Combinatorial Biosynthesis of Complex Carbohydrates …
c Biosynthesis of Starch and SucroseDuring active photosynthesis in bright light, a plant leafproduces more carbohydrate (as triose phosphates)than it needs for generating energy or synthesizing precursors.
Variation in the Complex Carbohydrate Biosynthesis …
Metabolism1.0 Global and overview maps1.1 Carbohydrate metabolism1.2 Energy metabolism1.3 Lipid metabolism1.4 Nucleotide metabolism1.5 Amino acid metabolism1.6 Metabolism of other amino acids1.7 Glycan biosynthesis and metabolism1.8 Metabolism of cofactors and vitamins1.9 Metabolism of terpenoids and polyketides1.10 Biosynthesis of other secondary metabolites1.11 Xenobiotics biodegradation and metabolism1.12 Chemical structure transformation maps