Enzymes, Biology

 

  • Biological catalysts à speed up chemical reactions in the body without being consumed in the process
    • Reduce the activation energy needed for reactants to reach the transition state

                        Don't change the ΔG

o   Heat can provide activation energy à denatures enzymes though =(

  • Substrate à the specific reactant that the enzyme acts on
  • Enzymes have a complex 3-D shape à means they are VERY specific on their substrate
  • Names of enzymes end in -ase
    • E.g. amylase catalyzes amylose into maltose
  • Active Sites
    • The site where the substrate binds
    • Small portion of the enzyme

                         Pocket/groove in the 3-D shape of the enzyme

o   As the substrate enters the active site

                          The functional groups in active site will react and cause the enzyme to change shape to accommodate the substrate

                           Known as the induced-fit model

  • Enzyme-substrate complex à enzyme with a substrate attached
  • Enzymes
    • Bend, stretch, change pH etc. to break or build bonds
    • Heat from the cell + enzyme activity = transition state
  • Enzyme activity
    • Increased with heat (too much denatures them though)
    • pH à can denature them (stomach enzymes work at pH of 2
    • some need cofactors

                  non-protein components (e.g. Zn2+ or Mn2+) that bind to active site or to substrate

o   coenzymes

                  organic non-protein cofactors (e.g. NAD+)

  • Inhibition of Enzymes
    • Competitive

                       Compete for active site

                       Reverse affect by increasing conc. of substrate

                 o   Non competitive

                     Attach to non-active-site site

  change shape of enzyme so the substrate doesn't fit or catalyzing action is reduced

  • Control of enzymes (either through reducing production of enzyme or through inhibition)
    • Allosteric sites à receptor sites a distance away from the active site

                   o    Activator

                         Stabilizes the active form of the enzyme

                   o   Allosteric Inhibitor

                           Stabilizes the inactive form of the enzyme

  • Feedback inhibition
    • A product formed later in a series of chemical reactions allosterically inhibits an enzyme working earlier on in the process

                         Enzyme is inhibited à Less products formed à less inhibitors à enzyme activity goes up à more products (inhibitors) formed

                 o   E.g. threonine is catalyzed into isoleucine

                          Isoleucine inhibits the first enzyme that would act on threonine

  • Milk à cheese
  • Creating wine
  • Brewing beer
  • Starch à ethanol
  • Removing stains

 

Posted Date: 8/20/2012 5:31:27 PM | Location : United States







Related Discussions:- Enzymes, Assignment Help, Ask Question on Enzymes, Get Answer, Expert's Help, Enzymes Discussions

Write discussion on Enzymes
Your posts are moderated
Related Questions
Change of Health Status Over Time Health of a nation can be gauged from the available information on death.Disaggregated data by causes of death is more reflective of the status

W A TER Occurence Water is the most abundant substance, covering 70% of earth's surface. It constitutes 60-90% of living cells.              5-6% in tooth e

What is the cost-benefit relationship regarding sewage treatment as a method to fight water pollution? To treat sewage is much cheaper for society. The non treated sewage pollu

Explain the Objectives of nutritional care? - To minimize the development of nutrient imbalance. - To maintain fluid and electrolyte homeostasis - To promote energy equil

Which of the below terms is used to explain the study of factors which influence flow characteristics of blood as it moves through the body? Is it: a) Anginology b) Hemodyna

Classification of hydrocolloids by function It must be clear to you now that gum ghatti, gum karaya, gum tragacanth ( classified as exudate gums) locust bean  gum, guar g

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4

Q. Can you explain Ventricular Tachycardia? The term is usually reserved for at least four or more beats and modified by the term non sustained. Short runs of non-sustained VT

Epidemiological Theory - Accident Causation Epidemiological theory of accident causation considers industrial hygiene that concerns environmental issues and may result in sick

What happens to transcription at the lac operon when lactose is absent and why? What happens to transcription at the lac operon when lactose is present and why? What happens