1 / 13

Overview of Glycolysis: Pathway, Regulation, and Key Outputs

Glycolysis is the universal metabolic pathway that oxidizes glucose into pyruvate, generating ATP and NADH in the process. Present in all organisms, glycolysis occurs in the cytosol of eukaryotic cells and is an anaerobic process, meaning it does not require oxygen. In aerobic conditions, pyruvate is further oxidized to CO2, while in anaerobic conditions, it can be fermented to lactate or ethanol. Key regulatory enzymes include hexokinase and phosphofructokinase, crucial for managing cellular energy needs during metabolic fluctuations. The net reaction produces 2 pyruvate, 2 ATP, and 2 NADH, highlighting its role in energy transfer.

akeenan
Télécharger la présentation

Overview of Glycolysis: Pathway, Regulation, and Key Outputs

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Glycolysis

  2. Glycolysis Overview • The Glycolytic pathway describes the oxidation of glucose to pyruvate with the generation of ATP and NADH • Glycolysis is a universal pathway; present in all organisms: from yeast to mammals. • In eukaryotes, glycolysis takes place in the cytosol • Glycolysis is anaerobic; it does not require oxygen. • In the presence of O2, pyruvate is further oxidized to CO2. • In the absence of O2, pyruvate can be fermented to lactate or ethanol.

  3. 3 regulated steps 10 steps No O2 Glucose Glycolysis Pyruvate Lactate Eric Niederhoffer SIU-SOM Energy (ATP) and metabolites Net Reaction: Glucose + 2NAD+ + 2 Pi + 2 ADP = 2 pyruvate + 2 ATP + 2 NADH + 2 H2O

  4. Outputs: 2 pyruvate 2 NADH 2 ADP 2 ATP (net gain) Glycolysis summary • Inputs: • Glucose • 2 NAD+ • 2 ATP • 4 ADP + 4P

  5. Regulation of Glycolysis • Steps 1, 3 and 10 are regulatory • First regulatory enzyme – Hexokinase (Step 1) • Hexokinase catalyses phosphorylation of Glucose > G-6-P • First reversible step of glycolysis • Glucose >>>>>>> G-6-P (lots) (rate of glycolysis low) • so Hexokinase inhibited (Feed back inhibition) • Glucose enters cell but since the hexokinase inactive it can readily diffuse back to the blood through the glucose transporter in the plasma membrane. • This step uses ATP so prevent wastage.

  6. Step 2 Phosphofructokinase • Is the rate limiting enzyme • Is inhibited by [H+] • Production of lactate leads to an increase in [H+] so Phosphofructokinase is inhibited. During vigorous exercise all the lactate can not be removed by the blood leading to a increase in [H+] causing muscle pain. • Is inhibited by ATP but stimulated by AMP and Pi • This shows that this enzyme is stimulated when the cell needs energy. • Is inhibited by citrate • Is an early intermediate in the TCA cycle. When the TCA cycle rises citrate is transported out of the mitochondria into the cytosol and inhibits Phosphofructokinase and so slows glycolysis.

  7. Step 10 • Pyruvate Kinase

  8. Summary of 10 steps

  9. Regulation

More Related