Chlorophyll b

Biosynthesis

The Chlorophyll b biosynthetic pathway utilizes a variety of enzymes. In most plants, chlorophyll is derived from glutamate and is synthesised along a branched pathway that is shared with heme and siroheme.
The initial steps incorporate glutamic acid into 5-aminolevulinic acid ; two molecules of ALA are then reduced to porphobilinogen, and four molecules of PBG are coupled, forming protoporphyrin IX.
Chlorophyll synthase is the enzyme that completes the biosynthesis of chlorophyll b by catalysing the reaction
This forms an ester of the carboxylic acid group in chlorophyllide b with the 20-carbon diterpene alcohol phytol.