Metabolism of Carbohydrates PDF

Metabolism of carbohydrates Assistance proff. Dr Majid Al-saadi veterinary public health Department REMEMBER that: C HO is synthesis in plants by Photosynthesis process in assist chlorophyll pigment and sun light : 12 CO2 + 12 H2O + sun light >>C6H12O6 + 6 O2 glucose con...

Metabolism of carbohydrates Assistance proff. Dr Majid Al-saadi veterinary public health Department REMEMBER that: C HO is synthesis in plants by Photosynthesis process in assist chlorophyll pigment and sun light : 12 CO2 + 12 H2O + sun light >>C6H12O6 + 6 O2 glucose convert by Respiration process to : C6H12O6 + 6 O2 >> 6 CO2 + 6 H2O these reactions are opposites – and this is important simple truth that all of earth is in a whole closed system  matbolisim of carbohydrate in ((monogastric)) carbohydrate digested in simple stomach to yield simple glucose molecules (monosaccharidesand) which absorbed directly from small intestine and finaly in order to metabolized in three fendamental ways: 1. To be used as an immediate source of energy 1. To serve as a precursor of liver & muscle glycogen. 2. To serve as a precursor of tissue triglycerides Metabolism of CHO in the cells according to body requrments ‫ تحلل الجلوكوز‬-1Glycolysis ‫ دورة كربس‬-2kereb cycle ‫ بناء الجاليكوجين‬-3Glycogenesis ‫ استحداث الجلوكوز‬-4Gluconeogenesis ‫ تحلل الجاليكوجين‬-5Glycogenolysis  1.Glucose utilizes as an immediate Source of Energy a - in monogastric Glucose the end product of digestion of the carbohydrates absorbed from mucosal wall of small intestine to blood stream to distributed to whole body cells. b - as soon as enter the cells a series of biological reactions be done in two stages according to requirement of the bodycells to energy. This occure In two reactions :- 1. First reaction is Glycolysis :. occur in the cell cytoplasm ((anaerobic)). In which Glucose Phosphorylation to Glu-6-P and ending with pyruvic acid (three carbon molecule compound) 1. Second reactions (Krebs cycle )in where pyruvate enter "mitochondria," and ((aerobically)) transfer to → acetyl-CoA → enter citric acid cycle through several reactions finally convert to energy as (ATP),CO2and H2o. ‫التحلل اجلاليكويل‬ ‫‪Glycolysis‬‬  Glycolysis defination : glycolysis is the metabolic process in cell cytoplasm or (anaerobic cellular respiratory reaction). In which glucose enters cells in active transport process and transfer to pyruvic acid (all glycolytic enzymes are found in the cell cytoplasim). Glycolysis include two phase: phase I: having five reactions (1-5), -starts with glucose and ends with glyceraldahyd 3. phosphate , These reactions are energy requirement 2 (ATP). Phase II: called- pay-off reactions - consists of five reactions (6-10) in which glucose convert glyceraldehyd 3. phosphate and ends with pyruvic acid which produce energy10 ( ATP). Important Note 1. Glucose is split into two molecules of D- Glyceraldehyde-3-phosphate, each step occurs twice per each molecule of glucose 2. all nine itermediate compound between glucose to pyruvat are phosphorelated) ( carry a negative charge) which lead to prevents passing through cell membranes and remain in cytoplasm. 3. At last Pyruvat can pass from cytosplasim to mitochondria since it isnt phosphorylated so it begin aerobic oxidation when entring the (Krebs cycle)  Control point of the glycolysis There are three control points in glycolysis according to cell requirment to energy 1. First step: transformation of Glucose to glucose 6-phosphate by Control of hexokinase enzyme. 2. step 3 : transform fructose 6-phosphate to fructose 1-6 diphosphate by Control of phospho-fructokinase enzyme. 3. Step 10 : transform the phospho- enolpyrovat into pyruvat by Control of pyruvate kinase enzyme. Fate of pyruvate produced from glycolysis  1. transform pyruvat to lactat in muscles anearopic reaction Anaerobic in muscles and in some bacteria pyruvat transform to lactic acid by lactat dehudrogenase enzyme as following : O O O O C + Lactate C C=O + NADH + H H-C- OH dehydrogenase CH 3 CH 3 Pyruvate Lactate + ‫ فوسفات‬-3 ‫جليسرالدهيد‬Pi NAD+ ‫الكتات‬ ‫ ثنائي فوسفو جليسيرات‬3،1 NADH + H+ ‫بايروفيت‬  2. Pyruvat transformation to ethanol- alcohol in yeast occur by a type of some microorganisms in two steps : 1. transform pyruvat to acetaldehyde with lost CO2 this reaction stimulate by Decarboxlayes enzyme in present of Co-enzyme thiamin- pyrophosphat. 2.Reduction of acetaldehyde and oxidation of NAD to NADH pyruvic acids + 2Pi + 2ADP + 2H+ 2 Ethanol + 2CO2 + 2ATP + 2H2O  ‫دورة كربس‬Krebs Cycle 3. pyruvat enter mitochondria in present of oxygen (aerobically ) to start a chains of reactions, to convert to :CO2 + H2O + (ATP)energy  ‫‪Krebs Cycle‬دورة كربس‬ ‫في وجود األكسجين ينتقل البيروفيت إلى الميتوكوندريا ليبدأ سلسلة ‬ ‫وطاقة‪CO2 + H2O.‬من تفاعالت األكسدة تنتهى بتحوله إلى‬ ‫‪ Mg2+‬وأيونات المغنسيوم ‪TPP‬وجود المرافق اإلنزيمي ثيامين بايروفوسفات‬  Control points in Kreb cycle 1. Befor entre the kereb cycle : in oxidation of pyruvat to Acetyl-coA :any increase in ATP, NADH.acetylcholine inhibits pyrovat dehydrogenase enzyme 2. Inside the kereb cycle, there are three control points B. An increasing in ATP, NADH inhibit citrate synthase result from step one. C. An increasing in ATP, NADH inhibit iso- citrat synthase result from step three D. An increasing in ATP, NADH inhibit alpha ketoglutrate dehydrogenase enzyme produce from step 4.  ‫بريوفيت‬ ‫‪‬‬ ‫‪‬‬ ‫أستيل مرافق إنزميي أ‬ ‫مرافق إنزميي أ‬ ‫سرتات‬ ‫أوكسالو أسيتات‬ ‫أيزوسرتات‬ ‫ماالت‬ ‫‪‬‬ ‫دورة كربس‬ ‫‪CO2‬‬ ‫‪NADH‬‬ ‫ألفا كيتو جلوتارات‬ ‫‪‬‬ ‫‪NADH‬‬ ‫فيومارات‬ ‫‪CO2‬‬ ‫سكسينايل مرافق إنزميي أ‬ ‫سكسينات‬ CHO Metabolism in rumenants  metabolism OF CHO in ruminants Important notes : 1. ruminant differ from non –ruminants in CHO metabolism by containing considerable amounts of cellulose , hemicelluloses ,lignin and water soluble CHO. These Complex carbohydrates digest into simple sugars , done by enzymes similar to microbial digestion of carbohydrates in non-ruminants. 2. Also the , Rumen fluids have about of 30 different kinds of bacteria and flagellated microorganism with range of 52-80 billion cells of bacteria and about 200-500 thousands cells of flagella in each malletier of rumen fluids 3. So, most simple sugars produced (monosaccharides) from the digestion of carbohydrates by microorganisms in the rumen rarely appear in the rumenal fluid and intestine because all this products are consumed directly by microorganisms itself within their cells.  The Final Products of CHO digestion in ruminants 1. Acids :Volatile Fatty acids (VFA) like acetic acid,propionc acid and butyric acid , some amino acids present in diet converted to fatty acids by deamination in the rumen microflora. 2. Gases: like CO2 (65%) CH4 (26-27%)N(7%)and trace amount of H2,O2and H2S. 3. Organic acids : Pyruvic acid ,succinic and lactic acid (as intermediate compound )  So, final products of CHO in rumenannts is acetic acid , propionic acid , butyric ,considered the main source of energy 1. Acetic acid formed about 70٪ utilized in the liver, a. oxidized to generate ATP. b. major source of acetyl CoA for synthesis of lipids, 2. Proprionic acid is formed about 20% completely removed from portal blood vein by the liver, a major substrate for gluconeogenesis, which is very important to the ruminant because no glucose reaches the small intestine for absorption. 3. Butyric acid, is formed about 10% comes out of the rumen as the ketone - beta- hydroxybutyric acid oxidized in many tissues for energy production. 4. while CH4 and CO2, H2S and N2O Greenhouse gases (are expulsed through eructation.