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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]
chlorophyllide b + phytyl diphosphate chlorophyll b + diphosphate This forms an ester of the carboxylic acid group in chlorophyllide b with the 20-carbon diterpene alcohol phytol . References
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.
Chlorophyllide a reductase (EC 1.3.7.15), also known as COR, is an enzyme with systematic name bacteriochlorophyllide-a:ferredoxin 7,8-oxidoreductase. [ 1 ] [ 2 ] It catalyses the following chemical reaction
chlorophyll + H 2 O = phytol + chlorophyllide. Chlorophyllase can be found in the chloroplast, thylakoid membrane and etioplast of at least higher plants such as ferns, mosses, brown and red algae and diatoms. Chlase is the catalyst for the hydrolysis of chlorophyll to produce chlorophyllide (also called Chlide) and phytol.
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]
Pheophytin a, i.e. chlorophyll a without the Mg 2+ ion.. Pheophytin or phaeophytin is a chemical compound that serves as the first electron carrier intermediate in the electron transfer pathway of Photosystem II (PS II) in plants, and the type II photosynthetic reaction center (RC P870) found in purple bacteria.