MEVALONATE PATHWAY

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MevalonatePathway

• Also known as HMG CoA (3-hydroxy-3-methylglutaryl
  CoenzymeA) or Mevalonate dependent route
• Precursor of terpenes and steroids production

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MevalonatePathway
1st step
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Formation of HMG-CoA
MevalonatePathway
HMG CoA Synthase
Acetyl CoA
Acetoacetyl CoA
HMG CoA
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Formaton of Mevalonate
MevalonatePathway
HMG CoA Reductase
Mevalonate
HMG CoA
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Formation of 5-phosphomavalonate
MevalonatePathway
Mevalonate kinase
5-phosphomevalonate
Mevalonate
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Formation of 5-pyrophospomevalonate
MevalonatePathway
Phosphomevalonate Kinase
5-phosphomevalonate
5-pyrophosphomevalonate
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Formation of IPP
MevalonatePathway
Mevalonate-5-pyrophosphate decarboxylase
5-pyrophosphomevalonate
3-isopentyl pyrophosphate
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Formation of DMAPP
MevalonatePathway
Isopentyl pyrophosphate isomerase
3-isopentyl pyrophosphate
Dimethylallyl pyrophosphate
These five carbons are responsible for
formation af all terpenes
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MevalonatePathway
TERPENES
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Terpenes
MevalonatePathway

• Terpenes are derived biosynthetically from units
  of  isoprene

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MevalonatePathway
JOINING ISOPRENE UNITS
individual isoprene units join head-to-tail
Head-to-Tail
an extra bond
Tail-to-Tail
The terms head-to-tail and tail-to-tail are often
used to describe how the isoprene units are
joined.
larger terpenoid units dimerize tail-to-tail
.. explained later
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MevalonatePathway
CLASSIFICATION OF TERPENES
TYPE OF NUMBER OF ISOPRENE TERPENE
CARBON ATOMS UNITS
one
hemiterpene
C5
two
terpene
C10
sesquiterpene
C15
three
diterpene
C20
four
sesterterpene
C25
five
triterpene
C30
six
C40
eight
tetraterpene
NOTE
hemi half di
two sesqui one and a half tri
three tetra four
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MevalonatePathway
SOME TERPENES (C10)
geraniol
menthol
rose and other flowers
peppermint
a-pinene
camphor
camphor tree
turpentine
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MevalonatePathway
SESQUITERPENES
guaiazulene
geranium oil
caryophyllene
oil of cloves
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MevalonatePathway
HOW TERPENES ARE FORMED?
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CONCATENATION OF C5 (ISOPRENE) UNITS
DMAPP
IPP
C5
C10
HEAD
C5
B
isopentenyl-PP 3,3-dimethylallyl-PP
C10
TAIL
geranyl-PP
C15
C20
C15
farnesyl-PP
C20
again
geranyl-geranyl-PP
EACH NEW UNIT IS JOINED HEAD-TO-TAIL
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DIMERIZATION OF C15 AND C20 UNITS
TAIL
rearrange
TAIL
dimerize
Enz-B
H-
NADH
NAD
JOINED SYMMETRICALLY TAIL-TO-TAIL
UNITS ARE JOINED TAIL-TO-TAIL
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