1 / 17

Enzymes

Enzymes. What Are Enzymes?. Most enzymes are proteins Act as catalysts to accelerate a reaction Not permanently changed in the process Can be reused. Enzymes. Are specific for what they will catalyze Are reusable End in – ase - Sucrase -Lactase -Maltase. How do enzymes work?.

joels
Download Presentation

Enzymes

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. Enzymes

  2. What Are Enzymes? • Most enzymes are proteins • Act as catalysts to accelerate a reaction • Not permanently changed in the process • Can be reused

  3. Enzymes • Are specific for what they will catalyze • Arereusable • End in –ase -Sucrase -Lactase -Maltase

  4. How do enzymes work? Enzymes work by weakening bonds of the reactant, which lowers activation energy (energy needed to start the reaction)

  5. Enzymes Without Enzyme With Enzyme Free Energy Free energy of activation Reactants Products Progress of the reaction

  6. Substrates Enzyme The substance (reactant) an enzyme acts on is the substrate Joins Substrate

  7. Active Site Enzyme • A restricted regionof an enzyme molecule which binds to the substrate. Active Site Enzyme + Substrate = ENZYME-SUBSTRATE COMPLEX Substrate

  8. How does a substrate fit with its enzyme? TWO MODELS: 1.) Lock-and-Key Model 2.) Induced Fit Model

  9. Lock-and-Key Active Sites are SPECIFIC and COMPLEMENTARY for their substrates. This is like a LOCK & KEY Idea of “1 substrate for 1 enzyme”

  10. Induced Fit • A change in the shape of an enzyme’s active site • Induced by the substrate Idea that 1 enzyme can have more than 1 substrate. Is still specific for its substrates, but may be more than 1

  11. Induced Fit Active Site substrate Enzyme induced fit • A change in the configuration (shape) of an enzyme’s activesite • Induced by the substrate.

  12. What Affects Enzyme Activity? • Three factors: 1. Environmental Conditions 2. Cofactors and Coenzymes 3. Enzyme Inhibitors

  13. Environmental Conditions 1. Extreme temperatures are the most dangerous - High fevers 2. pH (most like 6 - 8 pH near neutral) 3. Ionic concentration (salt ions) ALL OF THESE FACTORS DISRUPT THE SHAPE OF THE ENZYME, SO IT WILL UNFOLD (DENATURE)

  14. Cofactors and Coenzymes 1. Metal ions (zinc, iron) = Cofactors (nonorganic) 2. Vitamins (biotin, B12)= Coenzymes (organic) • Sometimes need for proper enzymatic activity…help to further speed up the reaction • Example:Iron (Cofactor) must be present in the structureof hemoglobin in order for it to pick up oxygen.

  15. Enzyme Inhibitors: 1st Type Enzyme Competitive inhibitor 1.Competitive inhibitors:chemicals that resemblean enzyme’s normal substrate and compete with it for the active site. Substrate

  16. Enzyme Inhibitors: 2nd Type 2. Noncompetitive inhibitors: Inhibitors that do not enter theactive site, but bind toanother partof the enzymecausing the enzyme to change its shape, which in turn alters the active site. Noncompetitive Inhibitor Enzyme active site altered Substrate

  17. Most are PROTEINS Act as CATALYSTS  ACTIVATION ENERGY SPEED  Reactions Provide an ACTIVE SITEto bind to its substrate and form an enzyme-substrate complex Are SPECIFIC for its substrate(s) Are REUSABLE(after converting a reactant to product, can do this multiple times!) POINTS TO REMEMBER

More Related