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. 2013 Dec 4;8(12):e79861. doi: 10.1371/journal.pone.0079861

Figure 1. Biosynthetic pathway of ecdysteroids.

Figure 1

From cholesterol to 20-hydroxyecdysone, the active steroid hormone. Characterized steps: Nvd, neverland, Rieske-domain oxygenase; Phm, Phantom, CYP306A1, 25-hydroxylase; Dib, Disembodied, CYP302A1, 22-hydroxylase; Sad, Shadow, CYP315A1, 2-hydroxylase; Shd, Shade, CYP314A1, 20-hydroxylase. Chemical modifications are shown in red on molecules. Putative steps of the “black box”, from 7-dehydro-cholesterol to 5ß-ketodiol, are represented within the dark grey box. [O] indicates oxidative step that might be catalyzed by a CYP enzyme. Some steps could be catalyzed by shroud, spook (CYP307A1) or spookier (CYP307A2). 5ßR: 5ß-reductase. 3ßHSD: 3ß-hydroxysteroid-dehydrogenase. Modified from Lafont et al. [4].