glycolysis y học

Carbohydrate Catabolism Catabolism Central Role of Glucose Overview of glycolysis Two phases of glycolysis Two phases of glycolysis Preparatory Phase Fig 14-2 Reaction 1: phosphorylation pg 526 Reaction 1: phosphorylation Fig 14-3 Hexokinase vs glucokinase Tissue-specific isozymes Fig 15-14 Glycogen phosphorylase is activated upon phosphorylation by phosphorylase kinase Glycogen phosphorylase is activated upon phosphorylation by phosphorylase kinase Phosphorylase kinase is activated upon phosphorylation by protein kinase A (PKA) Glycogen phosphorylase is activated upon phosphorylation by phosphorylase kinase Phosphorylase kinase is activated upon phosphorylation by protein kinase A (PKA) PKA is activated by cyclic AMP, which is produced by a G-protein in response to epinephrine/glucagon Fig 14-1 NADPH is necessary to protect against reactive oxygen species Transketolase requires thiamine pyrophospate (TPP) as a coenzyme Ribose 5-P is necessary in rapidly dividing cells Oxidative phase •Rxns and produce NADPH •Rxn produces ribose-5phosphate Glucose 6-P + NADP+ + H2O  Ribose 5-P + NADPH + H+ + CO2 From C1 Key Enzyme: G6P Dehydrogenase Case Study Omar’s mother noticed that every time she served falafel, her son complained of feeling tired, hot, headachy, and sick to his stomach At first she thought he was just being fussy, but sometimes he would actually look yellow Medical testing confirmed hemolytic anemia What’s up with Omar? Divicine leads to reactive oxygen species Favism! A deficiency in G6PDH is the most common human enzyme defect, affecting more than 400 million people worldwide Protective against malaria Case Study Omar’s mother noticed that every time she served falafel, her son complained of feeling tired, hot, headachy, and sick to his stomach At first she thought he was just being fussy, but sometimes he would actually look yellow Medical testing confirmed hemolytic anemia What’s up with Omar? X Regulation G6P dehydrogenase is allosterically inhibited by NADPH; activated by NADP+ Oxidative Phase Glucose 6-P + NADP+ + H2O  Ribose 5-P + NADPH + H+ + CO2 Some cells need NADPH but not ribose 5-P Ribose 5-P can be recycled in the nonoxidative phase Pentose Phosphate Pathway: Nonoxidative Phase Fig 14-22 Fig 14-23 Ribose 5-phosphate Carbon Shuffling Reactions Glucose 6-phosphate Fig 14-23 ...Catabolism Central Role of Glucose Overview of glycolysis Two phases of glycolysis Two phases of glycolysis Preparatory Phase Fig 14-2 Reaction 1: phosphorylation pg 526... https://www.youtube.com/watch?v=EfGlznwfu9U Efficiency Feeder Pathways  All carbohydrate s enter glycolysis  In muscle, often via hexokinase glycerol Glycerol 3-P Fig 14-9 Case Study A 9-month-old... Breakdown Phosphoglucomutase Fig 15-29  G6P fate depends on tissue  In muscle, G6P proceeds through glycolysis  In liver, G6P is converted to glucose Limit Dextrins Glycogen Breakdown Debranching