Biology Reference
In-Depth Information
Chapter 10
The Chl a Carboxylic Biosynthetic Routes:
Conversion of Chlide a to Chl a
The first step in accomplishing anything is the belief that it can
be done.
Most of the chlorophyll a (Chl a ) in higher and lower plants is formed by esterification
of chlorophyllide a (Chlide a )(Fig. 10.1 ). A minor Chl a fraction esterified with
long chain fatty acids (LCFA) other than phytol is also formed from MV protochlo-
rophyllide a E (Pchlide a E) as described in Chap. 11 . In this section emphasis will
be placed on the biosynthetic heterogeneity of Chl a formed by esterification of
Chlide a with phytol.
10.1 Chlorophyll
a
Biosynthetic Heterogeneity
The biosynthetic heterogeneity of the Chl a of green plants is extremely complex.
In addition to the DV andMV chemical heterogeneity of the Chl a chromophore, and
the chemical and spatial biosynthetic heterogeneity of its immediate precursor,
Chlide a (see Chap. 9 ) , another layer of biosynthetic heterogeneity is imposed by
the esterification process. Indeed, although in green plants, most of the Chl a is
esterified with phytol (C 20 H 39 OH), conversion of Chlide a to Chlide a -phytol
appears to follow different routes in etiolated and green tissues ( vide infra ).
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