The Chl a Carboxylic Biosynthetic Routes: Reactions Between Mg-Protoporphyrin IX and Protochlorophyllide a - Chlorophyll Biosynthesis and Technological Applications - page 207

ALA ALA ALA

ALA

10 11 12

0'

DV Proto

DV Proto DV Proto DV Proto

0'

12

13

DV Mg-Proto DV Mg-Proto DV Mg-Proto

DV Mg-Proto

10

11 DV Mpe

0'

12 4VMPR

13

DV Mpe DV Mpe DV Mpe

DV Pchlide a

MV Mg-Proto

0' POR-A 13

12

DV Pchlide a DV Pchlide a

DV Chlide a

MV Mpe MV Mpe

4VPideR 10

4VPideR 11

4VCR

13

12

0'

M V Chlide a

M V Pchlide a M V Pchlide a

MV Pchlide a

13

MV Pchlide a

10

POR-B 11

15D

12

MV Chl a

POR-A

M V Chlide a

MV Pchlide b

4VPideR 14

0'

MV Chlide b

MV Chlide a

MV Chlide a

M V Chlide a

11

15D

10

12

0'

M V Chlide b

14

MV Chlide a E

MV Chl a

MV Chl a

MV Chl a

11

0'

12

10

MV Chl b MV Chl b

MV Chl b

MV Chl b MV Chl b

Fig. 7.12 Biosynthetic routes 10, 11, 0 0 and 13 which are responsible for the formation of DV
Mpe in LMV-DDV-LDMV plant species. Routes 10, 11, 0 0 and 13 are highlighted in green
(Adapted from Fig. 6.4 of Chap. 6 , and from Kolossov and Rebeiz 2010 )

source of enzyme, it is not possible to assign with certainty a precise mechanism for
its action without precise knowledge of the DV or MV nature of the Mpe substrate.
In Fig. 7.11 , three DV Mpe pools are depicted as being formed from DV Mg-Proto
via routes 1, 0 and 8. At this stage it is unclear whether the spatial biosynthetic
heterogeneity indicated by multiple resonance excitation energy transfer bands
(Table 6.1 ,Chap. 6 ) is accompanied by chemical biosynthetic heterogeneity or not. In
other words, it is unclear whether the biosynthesis of DV Mpe from DV Mg-Proto via
routes 1, 0 and 8 is catalyzed by identical SAMMTs or by SAMMT isozymes.