carbohydrates metabolism

• carbohydrates is a polymers of sugar linked together by glycosidic bonds
• glucose is a C6(H2O)6
• glucose is the most important biochemically important carbohydrates
• the metabolism starts in mouth because it has salivary amylase
• the hydrolysis does not continue in stomach because it is only in protein digestion.
• polysaccharides will hydrolyse in small intestine
• disaccharides will hydrolyse in the intestinal mucosal cells
• glycolysis is breaking down of glucose to form pyruvate
• gluconeogenesis is the formation of glucose from non carbohydrate substances
• glycogenesis is forming a storage of glucose; you convert it to glycogen
• glycogenolysis is breaking down of glycogen chain 1 by 1
• the site of glycolysis is in the cytosol of all cell
• substrate in glycolysis is glucose
• the rate limiting enzyme in glycolysis is phosphofructokinase
• the product of glycolysis is pyruvate, NADH, and ATP
• formation is glucose-6-phosphate uses enzyme hexokinase

  reaction: phosphorylation using ATP
• formation of fructose-6-phosphate uses enzyme phosphoglucoisomerase
• reaction used in formation of fructose-6-phosphate is isomerization
• formation of fructose-6-phosphate

  G-6-℗ is rearranged from a 6-membered ring into a 5-membered ring;

  C1 is no longer part of the ring structure
• formation of fructose-1,3-bisphosphate

  enzyme: phosphofructokinase
• formation of fructose-1,3-phosphate

  enzyme: phosphorylation using ATP
• formation of fructose-1,3-bisphosphate

  P from ATP bind to the 1st carbon of fructose-3-phosphate
• Formation of Triose Phosphates

  • Reaction: Cleavage (Lyase)

  • Enzyme: Aldolase

  • Fructose-1,6-Bis℗ (C6) is cleaved into two 3 carbon molecules
• Isomerization of Triose Phosphates

  • Reaction: Isomerization

  • Enzyme: Triosephosphate isomerase

  • DHA℗ is rearranged to form Glyceraldehyde-3-℗
• Formation of 1,3-Bisphosphoglycerate

  • Reaction: Oxidation & Phosphorylation

  • Enzyme: Glyceraldehyde 3-phosphate dehydrogenase

  • ℗i added to C1 of Glyceraldehyde-3-℗

  • Hydrogen of Aldehyde group binds with NAD+ to form NADH
• Formation of 3-Phosphoglycerate

  • Reaction: Substrate-level Phosphorylation

  • Enzyme: Phosphoglycerokinase

  • ℗ removed from C1 is transferred to an ADP molecule, forming ATP

  • substrate-level phosphorylation
• Formation of 2-Phosphoglycerate

  • Reaction: Isomerization

  • Enzyme: Phosphoglyceromutase

  • ℗ is moved from C3 to C2
• Formation of Phosphoenolpyruvate

  • Reaction: Dehydration

  • Enzyme: Enolase

  • Alcohol dehydration produces a –C=C– bond
• Formation of Pyruvate

  • Reaction: Substrate-level Phosphorylation

  • Enzyme: Pyruvate Kinase

  • ℗ removed from C2 is transferred to an ADP molecule, forming ATP

  • substrate-level phosphorylation
• the step 1 of gluconeogenisis is pyruvate carboxylase
• the step 2 of gluconeogenesis is phosphoenol pyruvate carboxykinase
• step 9 of gluconeogenesis is fructose-1,6-phosphatase
• the formation of glucose of glucpse6-phosphatse in gluconeogenesis uses glucose-6-phosphatase