Nat Pro 20
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Transcript of Nat Pro 20
SHIKIMIC ACID PATHWAY
THE SHIKIMIC ACID PATHWAYTHE SHIKIMIC ACID PATHWAYThis pathway (unique to plants) leads to the formation of the aromatic amino acids phenylalanine and tyrosine and to the formation of many other phenyl-C3 compounds.
Cleavage of the C3 side chain leads to many phenyl-C1 compounds.
C C C PhenylpropanoidsPhenylpropanoidsPhenyl-C3
CC C C
Phenyl-C1
glycolysis
PEP
GLUCOSE
Acetyl-CoA
pentose phosphatepathway
Erythrose-4-phosphatePhosphoenol pyruvate
Shikimic Acid
ORIGINS OF THEORIGINS OF THESHIKIMIC ACIDSHIKIMIC ACIDPATHWAYPATHWAY
The pentose phosphatepathway is one that converts glucose intosugars of different sizes(different numbers of C)by acyl interchanges.Erythrose is a 4-carbonsugar.
OH PO
OO C
CH2
COOH
O
OH HCH2
OHH
H
PO
H+
HO
H
erythrose-4-phosphate
phosphoenol pyruvate
O CCH2
COOH
OH
OH H
OHH
H
CH2OP
O
O
OH
O CCH2
COOH
OH
OH H
CH2 H
OH
H+
OOH
OH
H
OHCOOH
OOH
OH
COOH
OHOH
OH
COOH
shikimic acid
NADPH
H+
FORMATION OF SHIKIMIC ACIDFORMATION OF SHIKIMIC ACID
B:
FORMATION OF CHORISMIC ACIDFORMATION OF CHORISMIC ACID
OHOH
OH
COOH
shikimic acid
ATPO
OHOH
COOH
PC OCH3
COOHpyruvic acid
H+
hydrolysisof PEP
OOH
O
COOH
P CCH3
COOHOHO
OHO
COOH
P C
CH2
COOH
H
OHO
COOH
C
CH2
COOH
chorismic acid
:B- H2O
nucleophilicaddition to C=O
- H3PO4
PREPHENIC ACIDPREPHENIC ACID
O CCH2
COOH
CO
OHH
OH
chorismic acid
Claisen TypeRearrangement
OH
H
CH2C
O
HOOC
CO
O H
prephenic acid
H OH
CH2HOOC CO
COOH
phenypyruvic acid
p-hydroxy-phenylpyruvicacid
NADP+NADPH
- CO2-H+ -H-
Prephenic acid can be converted to phenylpyruvic acidor to 4-hydroxyphenylpyruvic acid:
tyrosine phenylalanine
- CO2-H+ -OH
pseudoaxial conformation
CLAISEN REARRANGEMENTCLAISEN REARRANGEMENT
OCHR
an allyl ether
heat OCHRH
OHCHR
an allyl phenol
enolization
H+
A THERMAL REARRANGEMENT
PREPHENIC ACID TO PHENYLALANINEPREPHENIC ACID TO PHENYLALANINE
OH
H
CH2C
O
HOOC
CO
O H
prephenic acid
:B-Enz
H+
CH2 CO
COOH
transamination
phenylpyruvic acid
CH2 CH COOHNH2
phenylalanine
- CO2- H2O
PREPHENIC ACID TO TYROSINEPREPHENIC ACID TO TYROSINE
OH
H
CH2C
O
HOOC
CO
O H
prephenic acid
:B-Enz
NAD+
CH2 CO
COOH
OH
transamination
4-hydroxyphenyl- pyruvic acid
CH2 CH COOH
OHNH2
tyrosine
hydride transferto NAD+
- CO2
CH2 CH COOH
OHNH2
tyrosine
CH2 CH COOHNH2
phenylalanine
PREPHENIC ACIDPREPHENIC ACID
phenylpyruvic acidphenylpyruvic acid 4-hydroxyphenylpyruvic acid4-hydroxyphenylpyruvic acid
X
PHENYLALANINE AND TYROSINE COME FROM PHENYLALANINE AND TYROSINE COME FROM A COMMON SOURCE AND ARE NOT CONVERTEDA COMMON SOURCE AND ARE NOT CONVERTED
Although most plants could convert phenylalanine to tyrosineusing hydroxylases, this conversion is a minor pathway. Mostplants make enough tyrosine without converting phenylalanine.
A PRELIMINARY OVERVIEW
CHORISMIC ACID
SHIKIMIC ACID
PREPHENIC ACID
TYROSINE
PHENYLALANINE
CINNAMIC ACIDS
ALKALOIDS ALKALOIDS
PHENYL-C3COMPOUNDS
ShikimatePathways
PHENYL-C1COMPOUNDS
FLAVONOIDS
(+ acetogenin piece)
CINNAMYL COMPOUNDSCINNAMYL COMPOUNDS
CINNAMYL COMPOUNDSCINNAMYL COMPOUNDSCH2 C
OCOOH
CH2 COH
COOHH
CH CH COOH
NADPH
- H2O
CH CH C S-Enz
O
CH CH C H
O
CO
H
oxidativecleavage
Enz-SH
NADPH
cinnamic acid
cinnamaldehyde
benzaldehyde
The rings can have various numbers of hydroxylor methoxyl groups (hydroxylases and SAM).
CH2 CH2 COOH
hydrocinnamic acid
FADH2
COOH COOH
OH
COOH
OHOH
COOH
OHOMe
COOH
OHOMeOH
p-coumaric acid caffeic acid ferulic acid
sinapic acid
COOH
OHOMeMeO
CH2OH
OH
CH2OH
OHOMe
CH2OH
OHOMeMeO
p-coumaryl alcohol
coniferyl alcohol
sinapylalcohol
SOME NATURALLY-OCCURING CINNAMYL COMPOUNDSSOME NATURALLY-OCCURING CINNAMYL COMPOUNDS
CINNAMICACID
correspondingaldehydes arealso found -see next slide
sinapic acid
COOH
OHOMeMeO
C
OHOMeMeO
OSCoA C
OHOMeMeO
OH CH2
OHOMeMeO
OH
HSCoA NADPH NADPH
sinapyl alcoholsinapyl aldehyde
TYPICAL REDUCTION SEQUENCESTYPICAL REDUCTION SEQUENCES
COOH
OMe OMe
CH2OH
OMe
OMe
anethole
estragole(methylchavicol)
CLEAVAGE TO CLEAVAGE TO PHENYL-C1 COMPOUNDSPHENYL-C1 COMPOUNDS
CLEAVAGE TO PHENYL-C1 COMPOUNDSCLEAVAGE TO PHENYL-C1 COMPOUNDS
COOH
OHMeO
OHMeO
C SCoAO
OHMeO
C SCoAO
OHCCH2
OHMeO
C SCoAO
O
C
OHMeO
OSCoA
SH
CoA:
C
OHMeO
OOH
vanillic acid
CH2
COOH
OHMeO
OH
H
C
OHMeO
OH
vanillin
reversealdol
reverseClaisen
H2O
H2O
H2O
ferulic acid
HSCoA NADP+
COUMARINSCOUMARINS
COOH COOH
OH OHCOOH
O OO OOH
umbelliferone
O OOH
OH
aesculetin
FORMATION OF COUMARINSFORMATION OF COUMARINS
isomerizationlactone(ester)
hydroxylase
coumarin
DICOUMAROL AND WARFARINDICOUMAROL AND WARFARIN
O O OO
OH OH
dicoumarol(sweet clover)
O
O
O
OH
Warfarin
O O
O
OO
OH
O O
OH
H C H
O
OH
CO
SCoA
OH
C CO
SCoA
O
..
:
- H2O
cinnamic acid
anti-coagulant
RODENTICIDE(rat poison)
causes internalbleeding in cows
FLAVONOIDSFLAVONOIDS
Plant Pigments
PLANT PIGMENTSPLANT PIGMENTSFlavonoids and anthocyanins are conspicuous plant pigments in nature thatare responsible for the beauty and splendor of flowers, fruits, fruit tree blossoms and of the autumn leaves.
Flavones are responsible for the yellow and orange colors; and the anthocyaninsare the source of red, violet and blue colors. These compounds occur mainly inhigher plants and are less common in the lower orders. You don’t find them inalgae, fungi or bacteria.
The flavonoids play a major role in attracting insects to feed and pollinate theseplants. Some of them also have a bitter taste and repel harmful insects like caterpillars.
Flavonoids are thought to be antioxidants, and play a major role in our diet, preventing the ravages of aging caused by free-radicals.
These compound have their biosynthetic origin in both the skimic acid pathwayand the acetogenin pathway - they are of hybrid origin.
NARINGENINNARINGENINO
CoAS
OH
malonyl-CoA3x
OHSCoA
OO
O
O
OH
OH O
OH
O
:
OH
OH O
OH
O
H
naringenin
A FLAVONE
internal Claisenand enolizations
A different starterthan acetyl-CoA.
acetogeninpathway
shikimic acidpathway
MIXED-ORIGINCOMPOUND
found in grapefruit
Michaeladdition
flavones are yellowor orange pigments
AnthocyaninFlower Pigments
Anthocyanin Leaf PigmentsAutumn Leaves
In Spring and Summerchlorophyll (green) masksthe anthocyanin colors.
OH
OH O
OH
O
R
naringenin (R=H)
OH
OH O
OH
OOH
R
OH
OH O
OH
OHOH
R
NADPH
[O]
OH
OH O
OH
OHOH
R
OH
OH
OH O
OH
OH
R
+
- 2 H2O
O2
pelargonidin (R=H)cyanidin (R=OH)
ANTHOCYANIDINS AND ANTHOCYANINSANTHOCYANIDINS AND ANTHOCYANINS
plant flower andleaf pigmentsANTHOCYANIDINS cyanidin is blue
pelargonidin is pink
Anthocyanins arered, violet or bluepigments.
SUMMARYSUMMARY
REPEAT
CHORISMIC ACID
SHIKIMIC ACID
PREPHENIC ACID
TYROSINE
PHENYLALANINE
CINNAMIC ACIDS
ALKALOIDS ALKALOIDS
PHENYL-C3COMPOUNDS
ANTHRANILIC ACID
TRYPTOPHAN
ALKALOIDS
ShikimatePathways
PHENYL-C1COMPOUNDS
FLAVONOIDS(+ acetogenin piece)
NEXTNEXTLECTURELECTURE