Logo of pnasPNASInfo for AuthorsSubscriptionsAboutThis Article
Proc Natl Acad Sci U S A. 1995 Jul 18; 92(15): 6743–6747.

An oleate 12-hydroxylase from Ricinus communis L. is a fatty acyl desaturase homolog.


Recent spectroscopic evidence implicating a binuclear iron site at the reaction center of fatty acyl desaturases suggested to us that certain fatty acyl hydroxylases may share significant amino acid sequence similarity with desaturases. To test this theory, we prepared a cDNA library from developing endosperm of the castor-oil plant (Ricinus communis L.) and obtained partial nucleotide sequences for 468 anonymous clones that were not expressed at high levels in leaves, a tissue deficient in 12-hydroxyoleic acid. This resulted in the identification of several cDNA clones encoding a polypeptide of 387 amino acids with a predicted molecular weight of 44,407 and with approximately 67% sequence homology to microsomal oleate desaturase from Arabidopsis. Expression of a full-length clone under control of the cauliflower mosaic virus 35S promoter in transgenic tobacco resulted in the accumulation of low levels of 12-hydroxyoleic acid in seeds, indicating that the clone encodes the castor oleate hydroxylase. These results suggest that fatty acyl desaturases and hydroxylases share similar reaction mechanisms and provide an example of enzyme evolution.

Full text

Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (1.3M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References.

Images in this article

Click on the image to see a larger version.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Morris LJ. The mechanism of ricinoleic acid biosynthesis in Ricinus communis seeds. Biochem Biophys Res Commun. 1967 Nov 17;29(3):311–315. [PubMed]
  • Galliard T, Stumpf PK. Fat metabolism in higher plants. 30. Enzymatic synthesis of ricinoleic acid by a microsomal preparation from developing Ricinus communis seeds. J Biol Chem. 1966 Dec 25;241(24):5806–5812. [PubMed]
  • Moreau RA, Stumpf PK. Recent studies of the enzymic synthesis of ricinoleic Acid by developing castor beans. Plant Physiol. 1981 Apr;67(4):672–676. [PMC free article] [PubMed]
  • Bafor M, Smith MA, Jonsson L, Stobart K, Stymne S. Ricinoleic acid biosynthesis and triacylglycerol assembly in microsomal preparations from developing castor-bean (Ricinus communis) endosperm. Biochem J. 1991 Dec 1;280(Pt 2):507–514. [PMC free article] [PubMed]
  • Smith MA, Jonsson L, Stymne S, Stobart K. Evidence for cytochrome b5 as an electron donor in ricinoleic acid biosynthesis in microsomal preparations from developing castor bean (Ricinus communis L.). Biochem J. 1992 Oct 1;287(Pt 1):141–144. [PMC free article] [PubMed]
  • Kearns EV, Hugly S, Somerville CR. The role of cytochrome b5 in delta 12 desaturation of oleic acid by microsomes of safflower (Carthamus tinctorius L.). Arch Biochem Biophys. 1991 Feb 1;284(2):431–436. [PubMed]
  • Fox BG, Shanklin J, Somerville C, Münck E. Stearoyl-acyl carrier protein delta 9 desaturase from Ricinus communis is a diiron-oxo protein. Proc Natl Acad Sci U S A. 1993 Mar 15;90(6):2486–2490. [PMC free article] [PubMed]
  • Fox BG, Shanklin J, Ai J, Loehr TM, Sanders-Loehr J. Resonance Raman evidence for an Fe-O-Fe center in stearoyl-ACP desaturase. Primary sequence identity with other diiron-oxo proteins. Biochemistry. 1994 Nov 1;33(43):12776–12786. [PubMed]
  • Shanklin J, Whittle E, Fox BG. Eight histidine residues are catalytically essential in a membrane-associated iron enzyme, stearoyl-CoA desaturase, and are conserved in alkane hydroxylase and xylene monooxygenase. Biochemistry. 1994 Nov 1;33(43):12787–12794. [PubMed]
  • Jones JD, Shlumukov L, Carland F, English J, Scofield SR, Bishop GJ, Harrison K. Effective vectors for transformation, expression of heterologous genes, and assaying transposon excision in transgenic plants. Transgenic Res. 1992 Nov;1(6):285–297. [PubMed]
  • Newman TC, Ohme-Takagi M, Taylor CB, Green PJ. DST sequences, highly conserved among plant SAUR genes, target reporter transcripts for rapid decay in tobacco. Plant Cell. 1993 Jun;5(6):701–714. [PMC free article] [PubMed]
  • Okuley J, Lightner J, Feldmann K, Yadav N, Lark E, Browse J. Arabidopsis FAD2 gene encodes the enzyme that is essential for polyunsaturated lipid synthesis. Plant Cell. 1994 Jan;6(1):147–158. [PMC free article] [PubMed]
  • Panaccione DG, Hanau RM. Characterization of two divergent beta-tubulin genes from Colletotrichum graminicola. Gene. 1990 Feb 14;86(2):163–170. [PubMed]
  • Stahl U, Banas A, Stymne S. Plant Microsomal Phospholipid Acyl Hydrolases Have Selectivities for Uncommon Fatty Acids. Plant Physiol. 1995 Mar;107(3):953–962. [PMC free article] [PubMed]
  • Bafor M, Jonsson L, Stobart AK, Stymne S. Regulation of triacylglycerol biosynthesis in embryos and microsomal preparations from the developing seeds of Cuphea lanceolata. Biochem J. 1990 Nov 15;272(1):31–38. [PMC free article] [PubMed]
  • Arondel V, Lemieux B, Hwang I, Gibson S, Goodman HM, Somerville CR. Map-based cloning of a gene controlling omega-3 fatty acid desaturation in Arabidopsis. Science. 1992 Nov 20;258(5086):1353–1355. [PubMed]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences


Save items

Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


  • Compound
    PubChem Compound links
  • MedGen
    Related information in MedGen
  • Nucleotide
    Published Nucleotide sequences
  • Protein
    Published protein sequences
  • PubMed
    PubMed citations for these articles
  • Substance
    PubChem Substance links

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...