4-423-08GlycolysisReg - 4 Enzyme regulation varies by...

Info icon This preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Net glycolysis reaction : Glucose + 2 Pi + 2 ADP + 2 NAD+ ======> 2 pyruvate + 2 ATP + 2 NADH + 2 H+ + 2HOH So: what is the point of glycolysis? -to make ATP -to make NADH (in aerobic organisms, a source eventually of more ATP) -to make pyruvate, in aerobic organisms the lead-in to the next stage of catabolism, the CAC
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
2 Glucose has other roles in the body besides just acting as a substrate for glycolysis WHY is it important to control a metabolic pathway? Logic of regulation: What does the pathway DO? ( make ATP, make pyruvate) (this gives us hints about what might regulate an enzyme) What makes a reaction a good candidate as a regulation point? The first reaction (Ex: hexokinase) (WHY?) Thermodynamically irreversible (Ex: hexokinase, PFK-1, PK) (WHY?) Unique or committed step (Ex: PFK-1) (WHY?)
Image of page 2
3 *Hexokinase Hexokinase (1st glycolytic rxn) is allosterically inhibited by high [G-6-P] (its product), which will accumulate if PFK-1 (3rd glycolytic rxn) is inhibited Control of enzyme Vo by high [P] = Feedback Inhibition
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 6
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 4 Enzyme regulation varies by location: (different cell compartments, different tissues) Enzymes that have the same kinetic job but different kinetic parameters = isozymes Muscle hexokinase Liver hexokinase (glucokinase) The liver isozyme, glucokinase, has a higher Km and is NOT inhibited by G-6-P (WHY?) What is the job of muscle cells? What is the job of liver cells? 5 A1. ATP is both a substrate and a product; And, at high [ATP] it is an allosteric inhibitor (binds at different site than the active site) A2. AMP is an allosteric activator PFK-1 is the most important regulatory point in glycolysis Allosterism 6 7 B. Citrate And C. Fructose 2,6 bisphosphate (F 2,6 BP) 8 C. …in _liver_, regulation of PFK-1 by F 2,6 BP 2 6 High [F 2,6 BP] activates PFK 1 Low [F 2,6 BP] inhibits PFK 1 9 * * *Pyruvate Kinase Pyruvate kinase allosterically inhibited by 1. High[ATP] 2. High[acetyl CoA] 3. High [fatty acids]...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern