?5-3?-hydroxysteroid dehydrogenase/?5-?4-ketosteroid isomerase (3?-HSD), a possible enzyme of cardiac glycoside biosynthesis, in cell cultures and plants of Digitalis lanata EHRH

Abstract

The in vitro transformation of pregnenolone into progesterone in Digitalis lanata tissues was shown to be catalyzed by a 3β-hydroxysteroid dehydrogenase/ketosteroid isomerase (3β-HSD). Product formation was monitored by HPLC. The enzyme could be partially characterized and 3β-HSD activities were measured in various Digitalis lanata tissues and in cell cultures of other plant species. Since no correlation was observed between biosynthetic competence of the tissue and 3β-HSD activity, it was concluded that this enzyme does not play a major role in regulating cardenolide biosynthesis.

Brassinosteroid Deficiency Due to Truncated Steroid 5α-Reductase Causes Dwarfism in thelkMutant of Pea

“…However, this intermediate has been investigated only in these two plants. The pathway of 5-en-3b-ol / 5-en-3-one / 4-en-3-one has been proposed for C 19/21 steroids in bacteria (Talalay and Wang, 1955), mammals , and plants (Seidel et al, 1990;Stuhlemmer and Kreis, 1996;Kreis et al, 1998;compare with Rhéaume et al, 1991;Simard et al, 1991). In contrast, D 5 -3bHSDs of Digitalis lanata (Finsterbusch et al, 1999) and Pseudomonas testosteroni (Yin et al, 1991) are soluble enzymes belonging to the short-chain dehydrogenase/reductase family.…”

Molecular cloning and heterologous expression of progesterone 5β-reductase from Digitalis lanata Ehrh.

“…An HPLC method (modified after Seidel et al, 1990) was applied to confirm the results from thin layer chromatography and to determine kinetic constants. The residue obtained after extraction and evaporation (see above) was dissolved in 50 ll methanol.…”

Plant Defense Responses in Opium Poppy Cell Cultures Revealed by Liquid Chromatography-Tandem Mass Spectrometry Proteomics

“…This protein contains 3␤-HSD and NmrA components. 3␤-HSD has been implicated in the biosynthesis of the steroid cardenolide in foxglove (Digitalis lanata) (69) and has been detected in potato and tobacco, suggesting a role in general steroid metabolism (70). In a proteomics survey of Panax ginseng, the abundance of 3␤-HSD increased in response to light and was linked to the biosynthesis of steroidal saponins (71).…”