Biology (? 40241)

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????? 3????????????????????????????????

• Biology (? 40241)

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????? 3 ???????????????????????????????? 3.1
???????????? 3.1.1 ??? 3.1.2 ??????? 3.2
??????????? 3.2.1 ???????????? 3.2.2
?????? 3.2.3 ????? 3.2.4 ???????????? 3.2.5
??????? 3.3 ??????????????????????????????????
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?????????????????????

• 1. ?????? ???????????????????????????????????????
  ???????????????????? ???????????????????????
• 2. ???????????? ????????? ??????????????????????
  ???????????????????
• 3. ???????????? ?????????????????????????????????
  ?? ??????????????????????????????????
  ?????????????????????????????????????

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??????????????????????????????????
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??????????????????????????????????

• 1. ??????????????????? (Exergonic reaction)
  ??????? ??????????????????????????????????????????
  ? ??????? ??????????????????????????
• 2. ??????????????????? (Endergonic reaction)
  ??????? ??????????????????????????????????????????
  ? ???????? ??????????????????????????

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?????????????????????????????????????????????????
????????????????????????????????????????
 ??????????????????????????????
 ??????????????????????????????????????????????
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?????????????????????????????????????????????????
??????????????  ??????????????????
 ????????????????
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??????????????????? (exergonic  reaction)
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??????????????????? (exergonic  reaction)
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??????????????????? (endergonic  reaction)
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??????????????????? (endergonic  reaction)
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http//io.uwinnipeg.ca/simmons/1115/cm1503/energy
.htm
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Catalysts these are substances that speed up
the reaction rate by lowering the "hill". That is
the reactants fo to products faster because the
catalyst lowers the activation energy needed to
get to the spontaneous reaction.
http//io.uwinnipeg.ca/simmons/1115/cm1503/energy
.htm
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Enzyme

• ?????????????????????????????????????????????? -
  ???????? ??? alcoholic fermentation
• 1871 (Louia Pasteur) ?????????????????????????????
  ?????????????????????????????????????????
• Liebig ???????????????????????????????????????????
  ????????? ???????????????????????????
• 1897 (Buchner) ???????????????????????????????????
  ???????????????

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Enzyme

• ????????????????????????????????????????
  ??????????????????????????????????????????????????
  ??????????????????????????????
• 1878 (Kuhne) ??????? enzyme ?????????????????
  ????????????????? ?????? in yeast

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Enzyme

• Enzyme ??????? ???????????????????????????????????
  ?????????????????????????????? (Catalyze)
  ??????????????? ?????????????????????????????????
  ? (activation energy)

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???????????????????????????????????

• 1. ???????????????????????????????????????????????
  ????? 108 - 1020 ???? ???????????????????????????
  ?????????????? ???
• 2. ????????????????????? ????????????????????????
  ????????????????? ? ??????
• 3. ???????????????????????????????????????????????
  ???? ????????????????????????
• 4. ??????????????????? (specificity)
  ????????????????????? (substrate specificity)
• 5. ???????????????????????????????????????????????
  ????????????????

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????????????????????? ??????????????????????????
??????????????? ? ??????
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??????????????????????????????

• Apoenzyme ?????????????????
• Cofactor ???????????????????
• 1. Coenzyme ??????????????? ???? NAD , NADP
  , FAD
• 2. Prosthetic group ???????????????? ????
  cytochrome oxidase ?? Fe ??????????????

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??????????????????

• ??????????????????????????????????????????????????
  ? ???????? ???????? (substrate)
• ????????????????????????????? ????????????????????
  ???????????????? ???????? ?????? ???? (active
  site) ?????????????????????????????
  ???????????????
• ??????? ?????????????????
• ???????? ????????????????????????????????????????
  ?????????
• ?????????????????????????????????????????????
  H2O2 ??? ?????????????? (catalase)
• ??????????????????????????????????????????????????
  ? ????????????????????????????????
  ????????????????? (Inhibitor) ????????????????????
  ???????? ????????? ???????????????????????
  ??????????????????????????? ??????????????????????
  ????????????
• ??????????????????????????????? ????????
  ???????????? (bond energy)

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An enzyme catalyzes the reaction of two
substrates to form one product.
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??????????????????????????????????????????????

• 1. ???????????????????????? (Lock and Key theory)
  ?????????????????????????? active site
  ????????????????? ???????????????????????????????
  ??????????????????????????????
• 2. ????????????????????? (Induced fit theory)
  ????????????????????? active site
  ???????????????????????????????????????????????

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Lock and Key Theory
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Induced-Fit Theory
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Induced-Fit Theory
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???????????????????????

• 1. ?????????????? substrate ?????????????????
  enzyme
• 2. ????????
• 3. ??????????? - ??? (pH)
• 4. ????????????????? (enzyme inhibitors)
• 4.1 ???????????????????? (competitive
  inhibitors)
• 4.2 ??????????????????????? (non-competitive
  inhibitors)
• 4.3 ??????????????????????????????????
  (uncompetitive inhibitors)

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Substrate concentration and enzyme concentration
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Temperature
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pH
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????????????????? (enzyme inhibitors)
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competitive inhibitors

• ??????????????????????????? active site
  ???????????????????????????????????????????????

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competitive inhibitors
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non-competitive inhibitors

• ????????????????????????????????????????????????
  ? ????????? active site ??????????????????????????
  ????? ?????????????????????

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non-competitive inhibitors
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non-competitive inhibitors
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activators  small molecules which attaches to
an allosteric enzyme and activates it, thus
increasing rates
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uncompetitive inhibitors

• ????????????????????????????????????????????????-?
  ??????? (ES-complex) ????????
  ???????-????????-?????????? (ESI-complex)
  ????????????????????????

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uncompetitive inhibitors
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Key Concepts

• Enzymes catalyze reactions by lowering the
  activation energy necessary for a reaction to
  occur. The molecule that an enzyme acts on is
  called the substrate. In an enzyme-mediated
  reaction, substrate molecules are changed, and
  product is formed. The enzyme molecule is
  unchanged after the reaction, and it can continue
  to catalyze the same type of reaction over and
  over

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Enzyme

• Each enzyme is specific for the reaction it will
  catalyze. In this laboratory,
• Enzyme catalaseSubstrate hydrogen peroxide
  (H2O2)Products water and oxygen
• H2O2 catalase H2O O2
• If a small amount of catalase is added to
  hydrogen peroxide, you will be able to observe
  bubbles of oxygen forming.

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Enzyme
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Enzyme Structure Enzymes are globular
proteins. Their folded conformation creates an
area known as the active site. The nature and
arrangement of amino acids in the active site
make it specific for only one type of substrate.
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Binding Specificity Even when different
substrate molecules are present, only those that
have the specific shape complementary to the
active site are able to bind with the enzyme's
active site.
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Induced Fit When an enzyme binds to the
appropriate substrate, subtle changes in the
active site occur. This alteration of the active
site is known as an induced fit. Induced fit
enhances catalysis, as the enzyme converts
substrate to product
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pH and Enzyme Function Each enzyme functions
best within a certain pH range. For example, the
enzyme pepsin, which works in your stomach,
functions best in a strongly acidic environment.
Lipase, an enzyme found in your small intestine,
works best in a basic environment.
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Conclusion

• ???????????????????????????????????? 2 ?????? ???
  ??????????????????? ??????????????????????
• ??????????????????????????????????????????????????
  ?????????????
• ??? pH , ???????? , ??????????????????????
  ?????????????????????????????????????????????
  ???????
• ??????????????????????????? ?????????????????????
  ??????????????????????????????????????????????????
  ??

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Reference

• ????????????????. ??????????????????.
  ?????????????? ??????????????????????. ????????
  2548
• http//61.19.145.7/student/science401/bio/bio3-1/c
  lub.html
• http//io.uwinnipeg.ca/simmons/1115/cm1503/energy
  .htm
• http//www.elmhurst.edu/chm/vchembook/573inhibit.
  html

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Thank you

• Miss Lampoei Puangmalai
• Major of biology
• Department of science
• St. Louis College Chachoengsao

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