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A brassinosteroid that is castasterone in which the oxo group at position 6 has been converted to a hydroxy group (the 6alpha-stereoisomer).

Identification

IUPAC Names

(22R,23R,24S)-5alpha-ergostane-2alpha,3alpha,6alpha,22,23-pentol

Molecular Formula
C28H50O5
Mass
466.703
Monoisotopic Mass
466.36582
Charge
0
InChI
InChI=1S/C28H50O5/c1-14(2)15(3)25(32)26(33)16(4)18-7-8-19-17-11-22(29)21-12-23(30)24(31)13-28(21,6)20(17)9-10-27(18,19)5/h14-26,29-33H,7-13H2,1-6H3/t15-,16-,17-,18+,19-,20-,21+,22-,23-,24+,25+,26+,27+,28+/m0/s1
InChIKey
CVXIEYXJQSRIAC-KLUYZAHOSA-N
SMILES
[H][C@@]1(CC[C@@]2([H])[C@]3([H])C[C@H](O)[C@@]4([H])C[C@H](O)[C@H](O)C[C@]4(C)[C@@]3([H])CC[C@]12C)[C@H](C)[C@@H](O)[C@H](O)[C@@H](C)C(C)C
Synonyms

6alpha-hydroxy-6-deoxocastasterone

6alpha-hydroxy-castasterone

6alpha-hydroxycastasterone

6alpha-Hydroxycastasterone

campestan-2alpha,3alpha,6alpha,22R,23R-pentol

Species

solanum lycopersicum

NCBI:txid4081 10.1002/chin.200322270

Europe PubMed Central results

Biosynthesis of brassinosteroids in cultured cells of Catharanthus roseus.

Author: Fujioka S, Noguchi T, Watanabe T, Takatsuto S, Yoshida S.

Abstract: Precursor administration experiments with 2H-labeled 6-oxocampestanol, 6-deoxocastasterone and 6alpha-hydroxycastasterone in cultured cells of Catharanthus roseus were performed and the metabolites were analyzed by GC-MS. [2H6]Cathasterone was identified as a metabolite of [2H6]6-oxocampestanol, whereas [2H6]6alpha-hydroxycastasterone and [2H6]castasterone were identified as metabolites of [2H6]6-deoxocastasterone, and [2H6]castasterone was identified as a metabolite of [2H6]6alpha-hydroxycastasterone, indicating that 6-deoxocastasterone is converted to castasterone via 6alpha-hydroxycastasterone. In addition, 6-deoxocathasterone, a putative biosynthetic intermediate in the late C6-oxidation pathway, was identified as an endogenous brassinosteroid. These studies provide further evidence supporting our proposed biosynthetic pathways for brassinolide.

Biosynthetic pathways of brassinolide in Arabidopsis.

Author: Noguchi T, Fujioka S, Choe S, Takatsuto S, Tax FE, Yoshida S, Feldmann KA.

Abstract: Our previous studies on the endogenous brassinosteroids (BRs) in Arabidopsis have provided suggestive evidence for the operation of the early C6-oxidation and the late C6-oxidation pathways, leading to brassinolide (BL) in Arabidopsis. However, to date the in vivo operation of these pathways has not been fully confirmed in this species. This paper describes metabolic studies using deuterium-labeled BRs in wild-type and BR-insensitive mutant (bri1) seedlings to establish the intermediates of the biosynthetic pathway of BL in Arabidopsis. The first evidence for the conversion of campestanol to 6-deoxocathasterone and the conversion of 6-deoxocathasterone to 6-deoxoteasterone is provided. The later biosynthetic steps (6-deoxoteasterone --> 3-dehydro-6-deoxoteasterone --> 6-deoxotyphasterol --> 6-deoxocastasterone --> 6alpha-hydroxycastasterone --> castasterone --> BL) were demonstrated by stepwise metabolic experiments. Therefore, these studies complete the documentation of the late C6-oxidation pathway. The biosynthetic sequence involved in the early C6-oxidation pathway (teasterone --> 3-dehydroteasterone --> typhasterol --> castasterone --> BL) was also demonstrated. These results show that both the early and late C6-oxidation pathways are functional in Arabidopsis. In addition we report two new observations: the presence of a new branch in the pathway, C6 oxidation of 6-deoxotyphasterol to typhasterol, and increased metabolic flow in BR-insensitive mutants.

The tomato DWARF enzyme catalyses C-6 oxidation in brassinosteroid biosynthesis.

Author: Bishop GJ, Nomura T, Yokota T, Harrison K, Noguchi T, Fujioka S, Takatsuto S, Jones JD, Kamiya Y.

Abstract: Brassinosteroids (BRs) are steroidal plant hormones essential for normal plant growth and development. Mutants in the biosynthesis or perception of BRs are usually dwarf. The tomato Dwarf gene (D), which was predicted to encode a cytochrome P450 enzyme (P450) with homology to other P450s involved in BR biosynthesis, was cloned previously. Here, we show that DWARF catalyses the C-6 oxidation of 6-deoxocastasterone (6-deoxoCS) to castasterone (CS), the immediate precursor of brassinolide. To do this, we first confirmed that the D cDNA complemented the mutant light- and dark-grown phenotypes of the extreme dwarf (dx) allele of tomato. To identify a substrate for the DWARF enzyme, exogenous application of BR intermediates to dx plants was carried out. C-6 oxoBR intermediates enhanced hypocotyl elongation whereas the C-6 deoxoBR, 6-deoxoCS, had little effect. Quantitative analysis of endogenous BR levels in tomato showed mainly the presence of 6-deoxoBRs. Furthermore, dx plants were found to lack CS and had a high level of 6-deoxoCS in comparison to D plants that had CS and a lower level of 6-deoxoCS. Confirmation that DWARF catalyzed the C-6 oxidation of 6-deoxoCS to CS was obtained by functional expression of DWARF in yeast. In these experiments, the intermediate 6alpha-hydroxycastasterone was identified, indicating that DWARF catalyzes two steps in BR biosynthesis. These data show that DWARF is involved in the C-6 oxidation in BR biosynthesis.