The Chl a Carboxylic Biosynthetic Routes: Reactions Between Mg-Protoporphyrin IX and Protochlorophyllide a - Chlorophyll Biosynthesis and Technological Applications - page 209

Fig. 7.14 Biosynthetic route 2 which is responsible for the formation of MV Mpe from MV
Mg-Proto in DDV-LDV-LDDV plant Species. Route 2 is in dark tan (Adapted from Fig. 6.3 of
Chap. 6 and from Kolossov and Rebeiz 2010 )
Biosynthesis of MV Mpe in DMV-LDV-LDMV Plant Species
In DMV-LDV-LDMV plant species, MV MPE is formed from DV Mg-Proto by
reduction of the vinyl group to ethyl at position 4 (ring B) of the macrocycle in one
thylakoid environment (Fig. 7.15 ) (Kim and Rebeiz 1996 ; Kolossov and Rebeiz
2010 ). The reaction is catalyzed by a [4-vinyl] Mg-Proto reductase (4VMPR) (Kim
and Rebeiz 1996 ).
The presence of this enzyme in DMV-LDV-LDMV plant species such as barley
was ascertained by detection of the enzyme in isolated barley etiochloroplasts
(Kolossov and Rebeiz 2010 ). The enzyme activity was solubilized from the barley
etiochloroplasts membranes by Chaps (Kolossov and Rebeiz 2010 ).
Metabolism of MV Mpe in DDV-LDV-LDDV Plant Species
The specific role of MV Mpe as a precursor of MV Pchlide a in DDV-LDV-LDDV
plant species was demonstrated by the strong conversion of exogenous MV Mpe to