Chlorophyll a is the primary form of chlorophyll in plants. Chlorophylls are pigments that give plants their perceived green colour and are essential for photosynthesis, the process by which light energy is converted into chemical energy. Chlorophyll a, in particular, absorbs energy from wavelengths of violet-blue and orange-red light. Two pathways exist for chlorophyll a biosynthesis whereby geranylgeranyl diphosphate and 3,8-divinyl chlorophyllide a becomes chlorophyll a. Both of these pathways take place in the chloroplast. This is the second pathway of chlorophyll a biosynthesis. First, 3,8-divinyl protochlorophyllide a 8-vinyl-reductase converts 3,8-divinyl chlorophyllide into chlorophyllide a. Second, chlorophyll synthetase uses magnesium ion as a cofactor to convert chlorophyllide a and geranylgeranyl diphosphate into geranylgeranyl chlorophyll a. The next three reactions to synthesize chlorophyll a from geranylgeranyl chlorophyll a are catalyzed by the same enzyme, geranylgeranyl dehydrogenase. It converts geranylgeranyl chlorophyll a into dihydrogeranylgeranyl chlorophyll a, dihydrogeranylgeranyl chlorophyll a into tetrahydrogeranylgeranyl chlorophyll a, and tetrahydrogeranylgeranyl chlorophyll a into chlorophyll a.

Chlorophyll a Biosynthesis II References