4-423-08GlycolysisReg

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

Info iconThis 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
Background image of page 1

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

View Full DocumentRight 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?)
Background 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
Background image of page 3

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

View Full DocumentRight Arrow Icon
Background image of page 4
Background image of page 5

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

View Full DocumentRight Arrow Icon
Background image of page 6
Background image of page 7

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

View Full DocumentRight Arrow Icon
Background image of page 8
Background 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

Page1 / 9

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

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online