Sterol C4-demethylation

Pascal, S., Taton, M. and Rahier, A. (1993) Plant sterol biosynthesis. Identification and characterization of two distinct microsomal oxidative enzymatic systems involved in sterol C4-demethylation. /. Biol. Chem., 268,11639-54. 

IDENTIFICATION OF THE COMPONENT REACTIONS OF OXIDATIVE STEROL C4-DEMETHYLATION... 

Two distinct component reactions of oxidative plant sterol C4-demethylation have been characterized. The 4a-carboxylic acid decarboxylase component will be further investigated. 

In addition, the present studies directly establish that remarkably the plant C4-demethylase systems are distinct from those involved in animal and yeast where removal of both C4 methyl-groups are sequentially catalyzed by the same enzymic system. Moreover, they indicate that in photosynthetic organisms, the sterol demethylations occur in the sequence 4,14,4 in contrast to animals and wild type yeast where the sequence is 14,4,4. Finally, the enzymes involved in the C4-demethylation complex could allow new opportunities for the design of inhibitors which should show useful herbicidal of fungicidal properties. 

Taton, M., Salmon, R, Pascal, S. and Rahier, A. (1994) Plant sterol biosynthesis recent advances in the understanding of oxidative demethylations at C4 and C14. Plant Physiol. Biochem., 32, 751-60. 

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