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SURVEY OF BIOCHEMISTRY Glycolysis. Announcements. Exam #2 on June 26 Chapters 7, 8, 11, 12, 14 Bring calculators Study Session with Vonda Thursday, June 26; 2-3:45 pm Boggs 228. Introduction to Glycolysis. Glycolysis: breakdown of sugars Primary start point = glucose
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Announcements • Exam #2 on June 26 • Chapters 7, 8, 11, 12, 14 • Bring calculators • Study Session with Vonda • Thursday, June 26; 2-3:45 pm • Boggs 228
Introduction to Glycolysis • Glycolysis: breakdown of sugars • Primary start point = glucose • 10 enzymatic reactions
Overview • Stage I of Glycolysis • 2 ATP’s invested • 1 Glucose is brokeninto 2 phosphorylated molecules
Overview • Stage II of Glycolysis • 4 ATP’s recovered • 2 NADH’s produced • GAP is converted to pyruvate
Enzymes in GlycolysisStage I: Energy Investment • Hexokinase • Uses ATP • Phosphoglucose Isomerase [PGI] • Phosphofructokinase [PFK] • Uses ATP • Aldolase • Splits 6C into two 3C molecules • Triose Phosphate Isomerase [TIM]
Enzymes in GlycolysisStage II: Energy Recovery • Glyceraldehyde 3-Phosphate Dehydrogenase • Uses NAD+ to form NADH • Phosphoglycerate Kinase [PGK] • Forms ATP (2 molecules) • Phosphoglycerate Mutase [PGM] • Enolase • Forms high energy molecule • Pyruvate Kinase [PK] • Forms ATP (2 molecules) Classify theseon board
Key Mechanisms • Kinases: Transfer PO32- to substrate • Phosphoglucose Isomerase • Aldolase • GAP Dehydrogenase • Phosphoglycerate Mutase
Example of Kinase Activity Step 1: Hexokinase
PGI Reaction Mechanism BaseCatalysis
PGI Reaction Mechanism AcidCatalysis
PGI Reaction Mechanism Base catalyzes ring closure H+
Glyceraldehyde 3-Phosphate Dehydrogenase Step 6 Remember:Glycolysis produces 2 molecules of GAP, and therefore 2 molecules of NADH
GAP Dehydrogenase Mechanism Free Enzyme
GAP Dehydrogenase Mechanism Thiol Addition
GAP Dehydrogenase Mechanism Dehydrogenation
GAP Dehydrogenase Mechanism PhosphateBinding Pi
PRS • What is the maximum number of O2 molecules that hemoglobin can bind? • One • Two • Three • Four
PRS • B cells mature in the ________. • Thymus • Bone marrow • Muscle tissue • Myosin
PRS • Oxygen binding to myoglobin results in what shaped curve? • Sigmoidal • Hyperbolic • Linear • Sinusoidal
PRS • Which of the following amino acids is not in the catalytic triad of serine proteases? • Ser • Thr • His • Asp
PRS • What is Km? • The catalytic efficiency • The catalytic rate constant • 1/2 Vmax • [S] at 1/2 Vmax