The Chl a Carboxylic Biosynthetic Routes: Protochlorophyllide a - Chlorophyll Biosynthesis and Technological Applications - page 222

Fig. 8.7 Biosynthetic routes 2, 3, 0, and 9 which are responsible for the formation of MV Pchlide
a in LDV-DDV-LDDV plant species. The routes are highlighted in yellow (Adapted from Fig. 6.3
of Chap. 6 , and from Kolossov and Rebeiz 2010 )
Biosynthesis of MV Pchlide a via Biosynthetic Route 2 in Etiolated and Greening
DDV-LDV-LDDV Plants During the Dark and Light Phases of the Photoperiod
Biosynthetic route 2 is initiated by reduction of the vinyl group at position 4 of the
DV Mg-proto macrocycle to ethyl, and conversion of DV Mg-proto to MV
Mg-proto. The reaction is catalyzed by 4VMPR (Kim et al. 1997 ; Kolossov and
Rebeiz 2010 ). The nascent MV Mg-Proto is then converted into MV Mpe and MV
Pchlide a as depicted in route 2 (Tripathy and Rebeiz 1986 ).
Biosynthesis of MV Pchlide a via Biosynthetic Route 3 in Etiolated DDV-LDV-
LDDV Plants in Darkness and in Green DDV-LDV-LDDV Plants During
the Dark and Light Phases of the Photoperiod
As depicted in Fig. 8.7 , MV Pchlide a can also be formed by reduction of the vinyl
group of DV Pchlide a to ethyl at position 4 of the macrocycle, via route 3. MV
Pchlide a formation can be accounted for by a slow conversion of DV Pchlide a to
MV Pchlide a , a reaction catalyzed by 4VCPideR during prolonged dark
incubations (Tripathy and Rebeiz 1988 ; Walker et al. 1988 ).