Slides 7 020212(2)

Slides 7 020212(2) - Lecture overview W e a r e n o w d is...

Info icon This preview shows pages 1–14. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture overview We are now discussing features of protein function Last lecture: Protein binding: how proteins interact with other molecules and other proteins to enable function Example: transport of oxygen by hemoglobin -Enzymes: Proteins as reaction catalysts (cooperativity) -Enzyme kinetics -Enzyme regulation Today!
Image of page 1

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

View Full Document Right Arrow Icon
Question of the day: why does a goose breast look so different from a chicken breast? Hint: the dark red is heme, but not in hemoglobin, Rather cytochromes that are mitochondrial localized Goose breast Chicken breast http://www.levanacooks.com/balsami-roasted-chicken-breasts/ http://www.slashfood.com/2010/03/24/sliced-goose-breast-feast-your-eyes/
Image of page 2
Today: Enzyme regulation 1) Inhibition of enzymes (kinetic analysis) I have posted a practice exam and key on Blackboard I will hold a recitation in preparation for the exam on Tuesday, Feb. 7 here in Leidy 10, 7:00-8:00 PM 2) Enzyme isoforms with differing properties 3) Enzyme complexes and local effects 4) Feedback inhibition Note: you can supplement reading for this lecture by pp. 194-205 and 220-228 In Lehninger, Principles of Biochemistry, 5th ed. the pdf’s are posted on Bb!! 5) Allosteric enzymes and activators/inhibitors 6) Enzyme regulation by covalent modification 7) Regulation by proteolytic cleavage 1a) Bisubstrate reactions
Image of page 3

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

View Full Document Right Arrow Icon
Focus on glycolysis (enzymes) Figure 2-88 Molecular Biology of the Cell (© Garland Science 2008) Hexokinase Phosphofructokinase Pyruvate Δ G in cell All enzymes In between (estimates) (kJ/mol) -27.2 -25.9 -13.9 All near 0 (slightly<0) Voet and Voet p. 625 These three enzymes are highly regulated!
Image of page 4
Key regulatory points Figure 2-88 Molecular Biology of the Cell (© Garland Science 2008) Hexokinase Phosphofructokinase Pyruvate dehydrogenase All enzymes In between Captures Gateway to glycolysis Branchpoint All near 0 (slightly<0) Voet and Voet p. 625 These three enzymes are highly regulated! glucose at end
Image of page 5

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

View Full Document Right Arrow Icon
Key regulatory points Hexokinase Phosphofructokinase All enzymes In between Captures Gateway to glycolysis Branchpoint All near 0 (slightly<0) glucose at end Pyruvate dehydrogenase Respiration Fermentation (responds to need) How much goes in Draws out product Keeps running at −Δ G
Image of page 6
Enzyme inhibition Many drugs function by enzyme inhibition Adderall Inhibits dopamine transporter (blocks reuptake from synapses) HIV protease inhibitor Viagra (shown bound in Active site of Pde-5) Inhibits Pde-5 (Stabilizes cGMP) Acetonephren (Advil) Inhibits Cox-2 (slows inflamation pathway) Inhibits viral multiplicaton
Image of page 7

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

View Full Document Right Arrow Icon
Competitive inhibition Binds into active site: reduces ability of substrate to bind (increases K m )
Image of page 8
Uncompetitive inhibition Binds to enzyme-substrate complex: lowers rate of catalysis
Image of page 9

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

View Full Document Right Arrow Icon
Mixed inhibition Binds to both enzyme alone and enzyme-substrate complex: reduces both substrate binding and rate of catalysis (increases K m and reduces V max )
Image of page 10
Image of page 11

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

View Full Document Right Arrow Icon
Competitive inhibition-kinetics Binds into active site: reduces ability of substrate to bind (increases K m ) Remember to invert!
Image of page 12
Competitive inhibition-kinetics Remember to invert!
Image of page 13

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

View Full Document Right Arrow Icon
Image of page 14
This is the end of the preview. Sign up to access the rest of the 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