Epithiospecifier protein from broccoli (Brassica oleracea L. ssp. italica) inhibits formation of the anticancer agent sulforaphane

Nathan V. Matusheski, Ranjan Swarup, John A. Juvik, Richard Mithen, Malcolm Bennett, Elizabeth H. Jeffery

Research output: Contribution to journalArticle

Abstract

In some cruciferous plants, epithiospecifier protein (ESP) directs myrosinase (EC 3.2.3.1)-catalyzed hydrolysis of alkenyl glucosinolates toward epithionitrile formation. Here, for the first time, we show that ESP activity is negatively correlated with the extent of formation of the health-promoting phytochemical sulforaphane in broccoli (Brassica oleracea L. ssp. italica). A 43 kDa protein with ESP activity and sequence homology to the ESP of Arabidopsis thaliana was cloned from the broccoli cv. Packman and expressed in Escherichia coli. In a model system, the recombinant protein not only directed myrosinase-dependent metabolism of the alkenyl glucosinolate epi-progoitrin [(2S)-2-hydroxy-3-butenyl glucosinolate] toward formation of an epithionitrile but also directed myrosinase-dependent hydrolysis of the glucosinolate glucoraphanin [4-(methylsulfinyl)butyl glucosinolate] to form sulforaphane nitrile, in place of the isothiocyanate sulforaphane. The importance of this finding is that, whereas sulforaphane has been shown to have anticarcinogenic properties, sulforaphane nitrile has not. Genetic manipulation designed to attenuate or eliminate expression of ESP in broccoli could increase the fractional conversion of glucoraphanin to sulforaphane, enhancing potential health benefits.

Original languageEnglish (US)
Pages (from-to)2069-2076
Number of pages8
JournalJournal of Agricultural and Food Chemistry
Volume54
Issue number6
DOIs
StatePublished - Mar 22 2006

Keywords

  • Brassica oleracea
  • Broccoli
  • Epithiospecifier protein
  • Glucosinolates
  • Sulforaphane
  • Sulforaphane nitrile

ASJC Scopus subject areas

  • Chemistry(all)
  • Agricultural and Biological Sciences(all)

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