| chlorophyll unit | The number of chlorophyll molecules required to reduce one molecule of carbon dioxide by photosynthesis. (05 Mar 2000) |
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| chlorophyll | The photosynthetic pigments of higher plants, but closely related to bacteriochlorophylls. Magnesium complexes of tetrapyrolles. (18 Nov 1997) |
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| chlorophyll a | Magnesium(II) pheophytinate a [(pheophytina to a)magnesium(II)];the major pigment found in all oxygen-evolving photosynthetic organisms (higher plants, and red and green algae). (05 Mar 2000) |
| chlorophyll b | (CH3 at 7 replaced by CHO in the chlorophyll structure), magnesium(II) pheophytinate b [(pheophytinato b) magnesium(II)]; the chlorophyll generally characteristic of higher plants (including the Chlorophyta, Euglenaphyta, and green algae). Absent in other types of algae. (05 Mar 2000) |
| chlorophyll b reductase | <enzyme> Reduces the 7-formyl group of chlorophyll b to the 7'-hydroxy compound; requires NADPH or NADH; NADPH is more effective Registry number: EC 1.1.1.- Synonym: chlorophyllide b reductase (26 Jun 1999) |
| chlorophyll c | The chlorophyll present in brown algae, diatoms, and flagellates. Two variants are known: c 1, 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. Synonym: chlorofucin. (05 Mar 2000) |
| chlorophyll d | -CH==CH2 replaced by -CO-CH3 in the chlorophyll structure;the chlorophyll found in red algae (Rhodophyceae), together with chlorophyll a. (05 Mar 2000) |
| chlorophyll esterase | A reversible hydrolyzing enzyme catalyzing the removal of the phytyl group from a chlorophyll, leaving a chlorophyllide. Synonym: chlorophyll esterase. (05 Mar 2000) |
| chlorophyll synthetase | <enzyme> Incorporates geranylgeraniol into chlorophyll; requires ATP; as of 11/80 not clear whether this is a synthetase or a combination of a kinase and a transferase Registry number: EC 6.1.- (26 Jun 1999) |
| water-soluble chlorophyll derivatives | The copper complex of sodium and/or potassium salts of saponified chlorophyll, used topically for deodorization of chronic lesions and to promote wound repair. (05 Mar 2000) |
| absolute unit | A unit whose value is constant regardless of place or time and not derived from dependent on gravitation. (05 Mar 2000) |
| alexin unit | The smallest amount (highest dilution) of complement that will cause haemolysis of a unit of red blood cells in the presence of a haemolysin unit. Synonym: alexin unit. (05 Mar 2000) |
| Allen-Doisy unit | The quantity of oestrogen capable of producing in a spayed mouse a characteristic change in the vaginal epithelium, namely, disappearance of leukocytes and appearance of cornified cells, as determined by a vaginal smear; equal approximately to one-half of an estrone unit. Synonym: mouse unit. (05 Mar 2000) |
| amboceptor unit | haemolysin unit |
| androgen unit | The androgenic activity of 100 ug (0.1 mg) of crystalline androsterone as assayed by the comb growth response in capons. (05 Mar 2000) |
| antigen unit | The smallest amount of antigen that, in the presence of specific antiserum, will fix 1 complement unit. (05 Mar 2000) |