Agriculture Reference
In-Depth Information
MEP pathway
all-
trans
- -carotene
IPP
OH
all-
trans
-zeaxanthin
HO
VDE
ZEP
OH
all-
trans
-antheraxanthin
O
HO
VDE
ZEP
OH
HO
all-
trans
-violaxanthin
O
HO
OH
NSY
HO
Isomerase?
O
HO
all-
trans
-neoxanthin
Isomerase?
O
O
HO
HO
9-
cis
-violaxanthin
9 -
cis
-neoxanthin
NSY?
O
HO
OH
OH
NCED
NCED
Plastid
Cytosol
Xan
O
CHO
HO
XD
ABAld
OH
O
COOH
CHO
HO
O
Xanthoxic acid
ABAO
MOSU
OH
CH
2
OH
O
Abscisic alcohol
OH
ABA
COOH
O
Fig. 2.2
ABA biosynthetic pathway in higher plants. The ABA precursor, a C40 carotenoid, is
synthesized from IPP originating from the MEP pathway.
Solid arrows
indicate one-step modi-
fication of an intermediate and
dashed arrows
represent multistep modifications of an interme-
diate. Enzyme names are given in
bold
. Abbreviations:
IPP
isopentenyl pyrophosphate,
ZEP
zeaxanthin epoxidase,
VDE
violaxanthin de-epoxidase,
NSY
neoxanthin synthase,
NCED
9-
cis
-
epoxycarotenoid dioxygenase,
XD
xanthoxin dehydrogenase,
ABAO
abscisic aldehyde oxidase,
MOSU
MoCo sulfurase,
Xan
xanthoxin,
ABAld
abscisic aldehyde
Search WWH ::
Custom Search