1. Chapter 5: Cellular Processes 5.15-5.16 Pg. 85 Enzyme Regulation Objective: I can identify and describe the different ways enzymes are regulated, based on what molecules are binding where. http://www.nce.ufrj.br/ginape/iga502/Material_aulas/enzyme.swfhttp://www.nce.ufrj.br/ginape/iga502/Material_aulas/enzyme.swf - Review the Basics / Enzymes Quick Guide

2. Enzyme Regulation How cell affects enzyme activity (rate) “on purpose”  regulate activity Can send “signal molecule”  binds enzyme in 2 ways: 1) Can bind directly to active site: prevents substrate bind  only repress 2) Can bind “elsewhere” on enzyme to change enzyme shape (allow OR prevent substrate binding) : activate or repress Allosteric enzymes: can change to other shape by signal molecule Allosteric site Faster/slower? Enzyme on/off?

3. Enzyme Regulation Names If repressor signal molecule binds to active site… Called competitive inhibition If repressor signal molecule binds to allosteric site… Enzyme changes shape Active site no longer fits Called noncompetitive inhibition Not all enzymes have an allosteric site Not all enzymes are allosteric… http://www.nce.ufrj.br/ginape/iga502/Material_aulas/enzyme.swfhttp://www.nce.ufrj.br/ginape/iga502/Material_aulas/enzyme.swf Enzyme Inhibitors

4. Allosteric Enzyme Regulation Repressor signal molecule Will change shape so CANNOT bind Activator signal molecule Will change shape so CAN bind Where signal come from? Active Site Allosteric Site http://bcs.whfreeman.com/thelifewire/content/chp06/0602002.html http://www.springer.com/cda/content/document/cda_downloaddocument/0602s.swf?SGWID=0-0-45-752220-0 http://www.stolaf.edu/people/giannini/flashanimat/enzymes/allosteric.swf http://www.nce.ufrj.br/ginape/iga502/Material_aulas/enzyme.swfhttp://www.nce.ufrj.br/ginape/iga502/Material_aulas/enzyme.swf - allosteric http://www.microbelibrary.org/images/sandrin/allosterism.htm

5. Feedback Inhibition System of enzyme regulation where product of reaction can be signal molecule (inhibition  repressor) Competitive feedback inhibition Product binds directly to active site Noncompetitive feedback inhibition Product binds to allosteric site Allows for self-regulation If too much product, stops catalysis (repress) If too little product, continues catalysis Binding not permanent (can diffuse away) Product http://www.zerobio.com/flashmx/enzyme_regulation.htm

6. (Biochemical) Metabolic Pathway A “chain” reaction Involves several enzymes (closeby) Product of one catalyzed reaction becomes substrate for next Desired product only made at end of pathway Similar to Assembly Line Allows for more precise control http://www.nce.ufrj.br/ginape/iga502/Material_aulas/enzyme.swfhttp://www.nce.ufrj.br/ginape/iga502/Material_aulas/enzyme.swf - Feedback Inhibition http://highered.mheducation.com/sites/0072943696/student_view0/chapter2/animation__feedback_inhibition_of_biochemical_pathways.html

7. Prepare for a mix/match of different regulations Noncompetitive Inhibition = allosteric enzyme with repressor (simple) Noncompetitive Feedback Inhibition = allosteric enzyme with product being repressor Noncompetitive Feedback Inhibition of a Biochemical Pathway = several enzymes with at least 1 st enzyme being allosteric and product of last enzyme being a repressor to 1 st enzyme