Carbohydrate bioconversions for the synthesis of L-pentoses.
Theoretical basis of the CNCPS (Cornell Net Carbohydrate and Protein System): sub-models I e II [animal feeding]
Synthesis of Carbohydrate-Based Antibiotics - …
glycolysis The principal metabolic pathway responsible for
oxidation of carbohydrate (glucose) to pyruvate during cellular
gluconeogenesis A metabolic pathway responsible for the
net synthesis of carbohydrate (glucose) from amino acids, lactate,
respiration The collection of metabolic pathways responsible
for the oxidation of glucose, amino acids, and fatty acids,
with the production of energy involving an electron transport
lipid A chemically diverse group of molecules that are insoluble
in water and other polar solvents.
supercooling The absence of freezing at or below the normal
freezing point of water.
metabolome A quantitative metabolite profi le associated
with a cellular process.
The chemical reactions of cells, linked together in series to form pathways, are collectively referred to as metabolism. Metabolic pathways are interdependent and exquisitely regulated for efficient extraction of energy from fuels and for synthesis of biological macro-molecules. Cellular processes produce unique chemical fingerprints or metabolite profiles, and a complete quantitative set of metabolic intermediates associated with a cellular process is referred to as the metabolome. Metabolomics is the study of changes in the metabo-lome that may arise from metabolic regulation or alteration in gene expression, or a combination of both mechanisms. Studies of metabolism and metabolomics are subject areas of biochemistry, which also includes the structural chemistry of biological molecules and the chemistry of molecular genetics.
Metabolic studies with insects have focused on the biochemical bases for the unique physiological capabilities of insects and their arthropod relatives. Early studies considered chemical content, individual chemical reactions, respiration, and metabolic rate. Much of this was discussed in Sir V. B. Wigglesworth’s The Principles of Insect Physiology that first appeared in 1939. With advances, other comprehensive reviews appeared, including D. Gilmour’s 1961 The Metabolism of Insects, the 1964 edition of Physiology of Insecta and in 1978 The Biochemistry of Insects, both edited by M. Rockstein. More recently, insect metabolism was described in several volumes of Comparative Insect Physiology Biochemistry and Pharmacology, edited by G. A. Kerkut and L. I. Gilbert (1985). A recent update is Comprehensive Molecular Insect Science, edited by L. I. Gilbert, K. Iatrou, and S. Gill (2005), but the coverage of metabolism is restricted.
Cu(I)-catalyzed azide–alkyne 1,3-dipolar cycloaddition (CuAAC), popularly known as the “click reaction”, serves as the most potent and highly dependable tool for facile construction of simple to complex architectures at the molecular level. Click-knitted threads of two exclusively different molecular entities have created some really interesting structures for more than 15 years with a broad spectrum of applicability, including in the fascinating fields of synthetic chemistry, medicinal science, biochemistry, pharmacology, material science, and catalysis. The unique properties of the carbohydrate moiety and the advantages of highly chemo- and regioselective click chemistry, such as mild reaction conditions, efficient performance with a wide range of solvents, and compatibility with different functionalities, together produce miraculous neoglycoconjugates and neoglycopolymers with various synthetic, biological, and pharmaceutical applications. In this review we highlight the successful advancement of Cu(I)-catalyzed click chemistry in glycoscience and its applications as well as future scope in different streams of applied sciences.
citric acid cycle and allows net synthesis of glucose ..
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.
Insects share with other invertebrates the common pathways of carbohydrate, lipid, and amino acid metabolism. Although much has been presumed based on overt similarities to more extensive studies of mammals and other higher taxa, many aspects of intermediary metabolism have been examined in a number of insects and different insect tissues. Much of intermediary metabolism, including synthesis and storage of carbohydrate and fat, takes place in the fat body.
Metabolism and utilization of the glucose disaccharide trehalose as the principal hemolymph or blood sugar is unique to insects and some other invertebrates. First described from an insect by G. R. Wyatt in pupae of the silk moth, Antheraea polyphemus, trehalose, a non-reducing sugar, occurs in many insects at variable but high levels. In lepidopteran insects, trehalose concentrations are commonly between 25 and 100 mM, levels greatly exceeding those of glucose in the blood of mammals. Blood glucose in man typically is about 5 mM, a low value for trehalose in hemolymph. With few exceptions, glucose occurs in insect hemolymph at levels less than 5 mM, and often at less than 1 mM. Trehalose serves multiple functions, as a storage carbohydrate that serves as a fuel for flight and as a cryopro-tectant, protecting insects from damage during overwintering in cold climes. The hemolymph level of trehalose plays an important role in regulating carbohydrate intake and maintaining nutritional home-ostasis. Levels of trehalose in the hemolymph are maintained by a complex interaction of nutrient intake and metabolism.
Trehalose is synthesized in the fat body from two glycolytic intermediates, glucose-1-phosphate and glucose-6-phosphate. The reactions are catalyzed by trehalose-6-phosphate synthase and trehalose-6-phosphate phosphatase. Sources of glucose for trehalose synthesis include dietary sucrose, glycogen, and gluconeogenesis; dietary sugar being the sole source of glucose under fed conditions. Trehalose formation from glycogen has been described in several insects including the cockroach Periplaneta americana and moth Manduca sexta during starvation. The breakdown of glycogen to glucose is due to activation of the enzyme glycogen phosphorylase and is under endocrine control by a neurohormone released from the corpora cardiaca in the brain. Induction of a “hypertrehalosemic” hormone RNA transcript in the central nervous system of the cockroach, Blaberus discoidalis, in response to starvation was recently demonstrated. Glucose synthesis, followed by trehalose formation, via gluconeogenesis, has only been reported in M. sexta and was induced when larvae were maintained on low carbohydrate diets. Starvation did not induce gluconeogenesis.
Insects obtain energy principally from aerobic respiration, but many species have some capacity for anaerobic energy metabolism when exposed to hypoxic or anoxic conditions. This is best known in aquatic insects such as midge larvae where the fermentation products may include lactate, ethanol, and acetate. The midge Chaoborus crystallinis accumulates succinate, suggesting that this species is able to use anaerobic respiration for ATP production.
Aarsland A, Wolfe RR: Effect of carbohydrate intake on net muscle ..
As we have seen, photosynthetic cells produce O2 (by the splitting of H2O)and use CO2 to produce 3-phosphoglycerate with a net gaseous changeduring photosynthesis that can be written as follow:
CO2 + H2O → O2 + (CH2O)
In the dark plants are carrying out mitochondrial respiration bythe oxidation of substrates to CO2 and theconversion of O2 to H2O. On top of that, there is another processin plants that, like mitochondrial respiration, consumesO2 and produces CO2 and, like photosynthesis, is drivenby light. This process is called photorespiration and is a costlyside reaction of photosynthesis. In this section we describethis process and the strategies plants use tominimize its metabolic consequences.
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.
Synthesis of Novel Carbohydrate Based Enzyme …
Software | Cornell Net Carbohydrate and Protein System
Gluconeogenesis Synthesis of glucose from non carbohydrate compounds is called “gluconeogenesis” Site : ..
Carbohydrate bioconversions for the synthesis of L …
As shown here, three CO2 are fixed for the net synthesis of one molecule of glyceraldehyde 3-phosphate.
Carbohydrate bioconversions for the synthesis of L-pentoses
Theory and validity of indirect calorimetry during net lipid synthesis
Chapter 19 : Carbohydrate Biosynthesis
Kovacs EM and MS Westerterp-Plantenga Effects of (-)-hydroxycitrate on net fat synthesis as de novo lipogenesis. Physiol Behav. (2006) May 23; [Epub ahead of print]
Carbohydrate metabolism - SlideShare
My comments: I choose this week’s study for two reasons as it addresses two separate issues, that of de novo lipogenesis (DNL, the synthesis of fat from carbohydrates) as well as the supplement hydroxycitric acid (HCA) which has been touted as a ‘fat-burner’ (for use on a fat loss diet) for quite some time.
Stoker chapter 24 Carbohydrate Metabolism
FIGURE 18–3 The three stages of CO2 assimilation in photosynthetic organisms. Stoichiometriesof three key intermediates (numbers in parentheses) reveal the fate of carbon atomsentering and leaving the cycle. As shown here, three CO2 are fixed for the net synthesis of onemolecule of glyceraldehyde 3-phosphate. This cycle is the photosynthetic carbon reductioncycle, or the Calvin cycle.
Is carbohydrate needed to further stimulate muscle …
Chourey PS, Taliercio EW, Carlson SJ and Ruan YL (1998) Genetic evidence that the two isozymes of sucrose synthase present in developing maize endosperm are critical, one for cell wall integrity and the other for starch biosynthesis. Molecular and General Genetics 259: 88–96.
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