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29 Cards in this Set
- Front
- Back
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mechanism by which glucose is trapped within the cell (other than the liver and kidney)
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phosphorylation
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transporter whose expression is upregulated by insulin
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GLUT4
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least saturable GLUT transporter (most responsive to increase glucose)
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GLUT2 (has highest Km)
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ATP synthesis, glycerol and acetyl CoA generation (for fat synthesis), alternate sugar synthesis, glycogen storage, NADPH synthesis (for reductive biosynthesis)
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possible uses of glycolysis
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only ATP generating reaction for medullary kidney and red blood cells
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glycolysis
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glycolytic pathway
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write out pathway (S115)
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result of glycolysis under anaerobic conditions
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lactate and NAD+
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result of glycolysis under aerobic conditions
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acetyl CoA (for TCA cycle) via pyruvate
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important regulatory enzymes of glycolysis
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hexokinase/glucokinase; phosphofructokinase-1 (PFK-1); pyruvate kinase
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ATP producing steps of glycolysis (enzymes)
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3-phosphoglycerate kinase, pyruvate kinase
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isoenzyme that is reponsive to glucose at high concentrations
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glucokinase
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isoenzyme that is operating at Vmax under normal levels (not directly after meals) of glucose; inhibited by glucose-6-P
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hexokinase
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the key regulated point in glycolysis (committed irreversible step); downregulated by high ATP levels and citrate; activated by AMP; requires Mg2+ and ATP
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phosphofructokinase-1 (PFK-1)
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generates ATP by substrate level phosophorylation
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phosphoglycerate kinase and pyruvate kinase
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overall reactants and products from glucose -> 2 pyruvate
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IN: 2 ADP + 2 Pi + 2 NAD+; OUT: 2 ATP + 2 NADH+ + 2H+
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mechanism of regenerating NAD+ during anaerobic glycolysis
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reduction of pyruvate to lactate(via lactate dehydrogenase)
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location of lactate reconversion to pyruvate
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liver (via lactate dehydrogenase)/The Cori Cycle
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how NAD+ is regenerated during aerobic glycolysis
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NADH participates in a reduction reaction that produces the "shuttles" malate (NADH in matrix) or glycerol-3-phosphate (FADH2 in matrix)
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how NAD+ is regenerated during anaerobic glycolysis
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pyruvate is reduced to lactate using lactate dehydrogenase (and can be converted back to pyruvate in the liver via the Cori cycle)
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second most important regulation step in glycolysis; activated by fructose-1,6 BP (feed forward mechanism) and inhibited by ATP
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pyruvate kinase
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the increased rate of glucose utilization during anaerobic glycolysis due to the inefficiency of ATP production in glycolysis
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Pasteur effect
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dephosphorylated by insulin; stimulates production of fructose 2,6-bisphosphate
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PFK-2 (phosphofructosekinase-2)
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activates PFK-1 in liver only; production is dependent on insulin/glucagon levels
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fructose 2,6-bisphosphate
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phosphorylated by glucagon; stimulates hydrolysis of fructose 2,6-bisphosphate to fructose 6-phosphate
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FBPase-2 (fructose-2,6-bisphosphatase)
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2nd most common deficiency that causes anemia due to hemolysis of RBCs; hemolysis occurs due to a decrease in ATP production due to a lack of one of the key regulation checkpoints/ATP production points of glycolysis; no Heinz bodies; leads to osmotic fragility due to the inability for the Na/K pump to work
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pyruvate kinase deficiency
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an additive to a blood tube that stops glycolysis (by inhibiting a setp ofthe coversion to pyruvate via enolase)
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NaF
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inhibits the affinity of O2 for hemoglobin allowing for oxygen delivery (dumping) to tissues that are highly glycolytic
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2,3-BPG
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prevents substrate level phosphorylation due to its similarity to phosphate, inhibiting to production of ATP leading to hemolytic anemia
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arsenic
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causes of lactic acidosis
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see last slide in S115 (glycolysis)
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