BCHM 3050 1st Edition Lecture 32 Outline of Last Lecture I Step 8 II Step 9 III Step 10 IV Pyruvate Kinase V Glucokinase vs Hexokinase VI Energy Investment VII Energy Payof VIII Regulation of Glycolysis IX Metabolic Fate of Pyruvate X Lactic Acid Fermentation XI Alcohol Fermentation XII Practice Questions Outline of Current Lecture I The Citric Acid Cycle II Summary of Reaction III Mitochondria Ultrastructure IV Overview of the Citric Acid Cycle V Enzymes of the Citric Acid Cycle VI Pyruvate Dehydrogenase VII Citrate Synthase VIII Succinate Dehydrogenase Current Lecture I II The Citric Acid Cycle a Krebs was Knighted as Sir Hans Krebs by Queen Elizabeth II in 1958 like Paul McCartney This is a British symbolic title of honor b Also called tricarboxylic cycle tricarboxylic molecule is used and citric acid cycle citric acid is the compound that is regenerated Summary of Reaction a Pyruvate is a 3 carbon atom containing molecule b 2 molecules of pyruvate at start c 4 NADH 1 FADH2 3 CO2 GTP are the products of this reaction d Enzyme converts pyruvate into acetyl coA which carries out the Krebs cycle pyruvate itself doesn t actually carry out the krebs cycle These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute III IV V e Pyruvate dehydrogenase is the enzyme that catalyzes the step before the start of the Krebs cycle f Inside of the mitochondria is the matrix where pyruvate dehydrogenase is found pyruvate processing pyruvate loses 2 CO2 forming acetyl coA 2 molecules of NADH formed g Start with 6 carbon glucose in glycolysis all carbon atoms are broken down and released at 6 CO2 molecules Mitochondria Ultrastructure a Localization of PDH complex thought to be loosely associated with inner membrane matrix interface b Thought to originally have been a prokaryote c Mitochondria has its own DNA d Krebs cycle and pyruvate processing occur in the matrix e Cristae folds is the same thing as the inner membrane f PDH pyruvate dehydrogenase complex is found on the inner member matrix Overview of the Citric Acid Cycle a Know how many carbon atoms are present in each state when CO2 NADH FADH ATP ADP are all released b Pyruvate is going to become completely oxidized into CO2 c Substrate level phosphorylation 1 ATP after each round of Krebs so 2 ATPs once both pyruvates have gone through the cycle d 3 carboxylic acid groups in citric acid Enzymes of the Citric Acid Cycle a Pyruvate dehydrogenase b Citrate synthase c Aconitase d Isocitrate dehydrogenase e a Ketoglutarate dehydrogenase f Succinyl CoA synthetase g Succinate dehydrogenase h Fumarase i Malate dehydrogenase j Enzymes labeled in yellow show where NADH or FADH2 are created k Step 1 Occurs in mitochondria matrix loses CO2 generates NADH oxidation reduction reaction pyruvate dehydrogenase belongs to the category of oxioreducatase enzymes l CoA 2 carbon atoms m Isocitrate 6 carbon atoms n Whenever you make an NADH enzyme is a dehydrogenase o Succinyl CoA synthetase converts succinyl coA to succinate only one that does substrate level phosphorylation to create ATP in this cycle p Succinate fumarate generates FADH2 oxioreducatase VI VII VIII q Break down bond of fumerate using water to created malate break in the presence of water is hydrolase r Malate oxaloacatate generate NADH oxioreductase Pyruvate Dehydrogenase a Thiamine pyrophosphate is derived from Thiamine vitamin B1 b Know the names of the enzymes co factors functions but not of copies c Someone with vitamin B deficiency does not make TPP cannot carry out respiration very well d Note The activators inhibitors of PDH are not acting via their inhibitory activating efects on PDH Kinase Each enzyme has their own binding sites for the same regulators e Glucose 6 phosphate can inhibit hexokinase product inhibits enzyme in step 1 for glycolysis f Acetyl coA product inhibits enzymes just like step 1 of glycolysis g Pyruvate dehydrogenase can be inactivated by phosphorylation i last enzyme in glycolysis pyruvate kinase is inhibited by phosphorylation Citrate Synthase a Acetyl Carbonion acetyl group where one of the CH3 protons falls away leaving CH2 CO SCoA radical b Enzyme is inhibits by its substrate ATP inhibits phosphofructokinase 1 yet ATP also serves as its substrate c Succinyl coA is a downstream inhibitor d Acetyl coA and OAA stimulate Succinate Dehydrogenase a Succinate dehydrogenase sits in the inner membrane and is part of the complex in the electron transport chain b ATP activates in this step rather than inhibiting like all of the other processes
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