chlorophyll

The magnesium complex of the phorbin derivative found in photosynthetic organisms; light-absorbing green plant pigments that, in living plants, convert light energy into oxidizing and reducing power, thus fixing CO₂ and evolving O₂; the naturally occurring forms are c. a, b, c, and d. SEE ALSO: phorbin.

- c. a magnesium(II) pheophytinate a [(pheophytinato a)magnesium(II)]; the major pigment found in all oxygen-evolving photosynthetic organisms (higher plants, and red and green algae).

- c. b (CH₃ at 7 replaced by CHO in the c. structure), magnesium(II) pheophytinate b [(pheophytinato b) magnesium(II)]; the c. generally characteristic of higher plants (including the Chlorophyta, Euglenaphyta, and green algae). Absent in other types of algae.

- c. c the c. present in brown algae, diatoms, and flagellates. Two variants are known: c₁, in which two hydrogens are lost from C-17 and C-18, thus resembling phytoporphyrin, and the side chain at C-17 becomes an acrylic residue, —CH=CH₂COOH; c₂, in which the same changes are noted, but two more hydrogens are lost from the ethyl group at C-8, making this a vinyl residue like that at C-3. The two compounds can thus be named in terms of phytoporphyrin : magnesium 3¹,3²,17¹,17²-tetradehydro-13²-(methoxycarbonyl)phytoporphyrinate and magnesium 3¹,3²,8¹,8²,17¹,17²-hexadehydro-13²-(methoxycarbonyl)phytoporphyrinate.

- c. d (—CH=CH₂ replaced by —CO—CH₃ in the c. structure), the c. found in red algae (Rhodophyceae), together with c. a.

- c. esterase SYN: chlorophyllase.

- water-soluble c. derivatives the copper complex of sodium and/or potassium salts of saponified c., used topically for deodorization of chronic lesions and to promote wound repair.

* * *

chlo·ro·phyll 'klōr-ə-.fil, 'klȯr-, -fəl n

1) the green photosynthetic coloring matter of plants found in chloroplasts and made up chiefly of a blue-black ester C₅₅H₇₂MgN₄O₅ and a dark green ester C₅₅H₇₀MgN₄O₆ called also respectively chlorophyll a, chlorophyll b

2) a waxy green chlorophyll-containing substance extracted from green plants and used as a coloring agent or deodorant

chlo·ro·phyl·lous .klōr-ə-'fil-əs, .klȯr- also chlo·ro·phyl·lose -'fil-.ōs, -(.)fil-' adj

* * *

n.

one of a group of green pigments, found in all green plants and some bacteria, that absorb light to provide energy for the synthesis of carbohydrates from carbon dioxide and water (photosynthesis). The two major chlorophylls, a and b, consist of a porphyrin/magnesium complex.

* * *

chlo·ro·phyll (klorґo-fil) [chloro- + Gr. phyllon leaf] any of a group of green magnesium-containing porphyrin derivatives occurring in all photosynthetic organisms. Chlorophylls act as respiratory pigments, converting light energy to reducing potential; the reduction of CO₂ is the first step in the synthesis of hexoses in photosynthetic organisms. Chlorophyll a occurs in all organisms exhibiting aerobic photosynthesis (green plants, algae, and cyanobacteria), chlorophyll b in higher plants, chlorophylls c₁ and c₂ in diatoms and brown algae, and chlorophyll d in red algae. Bacteriochlorophylls occur in bacteria exhibiting anaerobic photosynthesis. Preparations of water-soluble chlorophyll salts are used as deodorizers; see chlorophyllin.