Chapter 3 Metabolism of Carbohydrate

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????
Chapter 3 Metabolism of Carbohydrate
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??? ?????? Biosynthesis of carbohydrates

• 1?????
• (p197?27? ????)
• 2?????
• (p154?25? ????????)
• 3. ????????
• (p176?26? ??????????)

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1. ????(photosynthesis)
??? (photo reaction)
??????????
??? (dark reaction)
4
??
???
5
??? (photo reaction)
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??? (photo reaction)

• In plants
• 2NADP 2ADP 2pi 2H2O? 2NADPHH
  2ATPO2
• In photobacteria
• NADP ADP pi H2A? NADPHH ATP A

Light (8hv)
Light
7
???/???
Light (8hv)
O2
chlorophyl
NADP
(CH2O)
2H 2e
ADP ATP
Actived chlorophyl
H2O
NADPHH
CO2
CO2H2O???(CH2O)nO2
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?????????????
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CO2???(???)
???? Calvin??
CO2?????
???? Hatch-Stack ??
5C
5C
Calvin cycle
3C
6C
3C
3C
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Calvin Cycle (????)
?
1,5-??????
3-?????
1,3-??????
5-?????
3-?????
3-?????
3-?????
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CO2?? (CO2 fixation)
?????
??
??
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CO2?? (CO2 fixation)
3-p-???
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???-1,5-??????/???(Rubisco)
2-?-3-?-D-????
The initial CO2 fixation is catalyzed by
ribulose 1,5- bisphosphate carboxylase/oxygenase
??????
?????(?????)
????
3-p-???
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(No Transcript)
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?HMP??
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Photosynthesis
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The Nobel Prize in Chemistry 1961
"for his research on the carbon dioxide
assimilation in plants "
Melvin Calvin USA University of California
Berkeley, CA, USA 1911-1997
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????????
3-p-???
?????
3-p-???
Rubisco?
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???? ( Hatch-Stack ??)
????
??????
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2. ????? (Gluconeogenesis)

• ????????????????????,????????????????????????
  ???????????????????????????????????120g ?????
• ???????????????????????????????????????,?????

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2. ????? (Gluconeogenesis)
??????
??????????
????????????
??????????????
PYRUVATE ? GLUCOSE
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2.1 ??????

• ??????????????????
• ?????????????,??????????
• ????????????,????????????????????????????

????????????????????????????????Glc???,???????????
????????
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??????????

• 1. Glucose ATP ? G-6-P ADP
• 2. F-6-P ATP ? F-1,6-diP ADP
• 3. PEP ADP ? Pyruvate ATP

????
??????
?????
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????????????
??(?)?
??(?)?
??????
PEP????
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2.2 ????????

• ?????????TCA?????????,??????????
• ?????
• ?????????????
• ?????????????????????
• ?????????????CoA??

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2.3 ????????
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2.3.1 ??????? Pyruvate?PEP
??????
????ADPPi
???CO2 ATP
PEP????
???? GTP
PEPCO2GDPPi
PyruvateATPGTP PEPADPGDP2Pi
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???????
PEP Pyruvate
acetyl-CoA
CO2
CO2 ATP
GDP
ADP Pi
oxaloacetate
GTP
Citrate
NADHH
NAD
malate
Pyruvate
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???????
Structure of Carboxybiotin.
Biotin-Binding Domain of Pyruvate Carboxylase.
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????????????
?
?

• ???????????????,????????????????

????
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2.3.2 Conversion of fructose 1,6-bisphosphate to
fructose 6-phosphate is the second bypassing step

• The reaction is catalyzed by Mg 2 -dependent
  fructose 1,6-bisphosphatase (instead of
  phosphofructokiase-1).

??-1,6-????
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2.3.3 The conversion of glucose 6-phosphate to
glucose is the last bypassing step

• The reaction is catalyzed by glucose
  6-phosphatase (instead of hexokiase).
• The enzyme is present on the lumen side of the ER
  membrane of hepatocytes (???) and renal (??)
  cells.
• The enzyme is not present in muscle or brain
  cells, where gluconeogenesis does not occur.

???-6-???
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G6Pase
? ?
Glucose 6-phosphatase converts glucose 6-P to
glucose in the ER lumen of liver and kidney
cells.
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Gluconeogenesis Pyruvate ? Glucose

• The enzymes in red belong to the gluconeogenic
  pathway. These reactions overcome the high
  negative free energy of the irreversible
  reactions of glycolysis.
• The enzymes in blue are held in common between
  the two pathways.
• 2Pyruvate4ATP2GTP2NADH6H2O?Glucose4ADP2GDPP
  i2NAD2H

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• 2.3.4 TCA???????????

??CoA,???????????
TCA???????????????????
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????????????-CoA ????????????????
??????
??????
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Fatty acid ? Glucose
??????
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• 2.3.5?????????

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• ?????????????????????

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Glucose
G6P PEP Acetyl-CoA
ATP ADP
Pi H2O
G6P
G6P
AMP ADP F2,6BP
ATP Citrate 3-P-Glycerate
F6P
ATP Citrate NADH
AMP ADP F2,6BP
F1,6P
GDP
?????,?????
PEP
CO2
FDP G6P
ADP
GTP
Oxaloacetate
ATP Citrate Ala Acetyl-CoA
ADP
ATP
Pyruvate
Acetyl-CoA
ATP
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Glycolysis and gluconeogenesis are reciprocally
regulated
?????
???
Insulin stimulates
Glucagon stimulates
A high AMP indicates that the energy charge is
low and signals the need for ATP.
High ATP and citrate indicate the energy
charge is high and intermediates are abundant.
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2.3.6 ??????????F-2,6-diP?????????
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2.3.7 ????-Futile Cycle

• ???????????????????????,?????????????ATP??,???????
  ??,?????????ATP????,??????????,???????????(Futil
  e cycle)?
• ??????????????,????3??????
• ???????????????

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????(Futile Cycle)
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2.3.8 The Cori Cycle (????)
Lactate from active muscle is converted to
glucose in liver.
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(No Transcript)
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3. ???????? Biosynthesis of glycogen and starch
P176
?????
?????
????
?????
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????
3.1 ?????
(1)
G-1-P
G-6-P
?G0 7.28 kJ/mol
UDP-????????
(2)

• G-1-P p-p-p-U UDP-G PPi
• ?G0 ?0 kJ/mol

2 Pi
?G0 -33.5 kJ/mol
p184
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3.2 ?????

????
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3.3 ?????

• ?????
• ??????(??????????)

?????11???
?????7??????
?????????
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????11???
????7??????
Glycogen-branching enzyme
7????????????????????????????4?????
?G0 -15.5 kJ/mol
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3.3 ??/?????

• ?????????,???????????????,??????????ADP-Glu?
• ???????,???????30-40??

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3.4 ?????(???)
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3.5 ???????????
?????????
???????
?????????
???????
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3.5 ???????????
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3.5 ???????????
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3.5 ???????????
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• 3.6 ?????????

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3.7 ???/??????
P164
UDP-???
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??? ?????(Metabolic Block)

• ???????????????
• 1??????????
• 2?????????

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5.1 ?????(Galactosemia)

• ??????galactose 1-phosphate uridyl
  transferase,???Gal-1-P???UDP-Gal,???????EMP,?????

??,??????,?????????,???????????????????????????,??
???????????
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• ?????(Galactosemia)??

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5.2 ????(Hexokinase)??

• ????,?????????,EMP????,2,3-dip-?????,?????O2????
  ???,????O2????,?????

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5.3 ?????(Pyr kinase)??

• ????????TCA,EMP??????,2,3-dip-GA??,?????O2??????
  ?ATP??,??Na.K-ATPase??,??????????????????,?????
  ???

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5.4 G-6-P dHE??

• ????????(?????????????)??????,?????????????????,
  ?????????,????????NADPH,???????GSH??,?????,???????
  ??

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5.5 ??? (Diabetes mellitus)

• Insulin????????,??????????????????????????????
  ?????,?????(hyperglycemia)?????????????,??????,???
  ?????????????????????????????????(ketonemia)????
  (acidosis).