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Chlorophyllide a, (R=H). In chlorophyllide b, the methyl group show in the green box is replaced with a formyl group. Chlorophyllide a, is a carboxylic acid (R=H). In chlorophyllide b, the methyl group at position 13 (IUPAC numbering for chlorophyllide a) and highlighted in the green box, is replaced with a formyl group.
This conversion forms an ester of the carboxylic acid group in chlorophyllide a with the 20-carbon diterpene alcohol phytol. Chlorophyll b is made by the same enzyme acting on chlorophyllide b. The same is known for chlorophyll d and f, both made from corresponding chlorophyllides ultimately made from chlorophyllide a. [39]
The systematic name of this enzyme class is chlorophyllide-a:NADP+ oxidoreductase. Other names in common use include 3,8-divinyl protochlorophyllide a 8-vinyl-reductase, [4-vinyl]chlorophyllide a reductase, and 4VCR. This enzyme is part of the biosynthetic pathway to chlorophylls. Protochlorophyllide, the product of the reaction
The Chlorophyll b biosynthetic pathway utilizes a variety of enzymes. [4] In most plants, chlorophyll is derived from glutamate and is synthesised along a branched pathway that is shared with heme and siroheme.
The enzyme that converts protochlorophyllide to chlorophyllide a, the next intermediate on the biosynthetic pathway, [4] is protochlorophyllide reductase, [5] EC 1.3.1.33. There are two structurally unrelated proteins with this activity: the light-dependent and the dark-operative. The light-dependent reductase needs light to operate.
Chlorophyll a is a specific form of chlorophyll used in oxygenic photosynthesis.It absorbs most energy from wavelengths of violet-blue and orange-red light, and it is a poor absorber of green and near-green portions of the spectrum. [3]
Chlorophyllide a, (R=H) is converted to chlorophyllide b, in which the methyl group show in the green box is oxidised to a formyl group. This enzyme contains a mononuclear iron centre and is part of the biosynthetic pathway to chlorophylls .
In enzymology, chlorophyll synthase (EC 2.5.1.62) is an enzyme that catalyzes the chemical reaction. chlorophyllide a + phytyl diphosphate chlorophyll a + diphosphate. The two substrates of this enzyme are chlorophyllide a and phytyl diphosphate; its two products are chlorophyll a and diphosphate.