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Epithiospecifier protein activity in broccoli: The link between terminal alkenyl glucosinolates and sulphoraphane nitrile

Williams, D.J. and Critchley, C. and Pun, S. and Nottingham, S. and O'Hare, T.J. (2008) Epithiospecifier protein activity in broccoli: The link between terminal alkenyl glucosinolates and sulphoraphane nitrile. Phytochemistry, 69 (16). pp. 2765-2773.

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Article Link(s): http://dx.doi.org/10.1016/j.phytochem.2008.09.018

Publisher URL: http://www.elsevier.com

Abstract

The chemical nature of the hydrolysis products from the glucosinolate-myrosinase system depends on the presence or absence of supplementary proteins, such as epithiospecifier proteins (ESPs). ESPs (non-catalytic cofactors of myrosinase) promote the formation of epithionitriles from terminal alkenyl glucosinolates and as recent evidence suggests, simple nitriles at the expense of isothiocyanates. The ratio of ESP activity to myrosinase activity is crucial in determining the proportion of these nitriles produced on hydrolysis. Sulphoraphane, a major isothiocyanate produced in broccoli seedlings, has been found to be a potent inducer of phase 2 detoxification enzymes. However, ESP may also support the formation of the non-inductive sulphoraphane nitrile. Our objective was to monitor changes in ESP activity during the development of broccoli seedlings and link these activity changes with myrosinase activity, the level of terminal alkenyl glucosinolates and sulphoraphane nitrile formed. Here, for the first time, we show ESP activity increases up to day 2 after germination before decreasing again to seed activity levels at day 5. These activity changes paralleled changes in myrosinase activity and terminal alkenyl glucosinolate content. There is a significant relationship between ESP activity and the formation of sulforaphane nitrile in broccoli seedlings. The significance of these findings for the health benefits conferred by eating broccoli seedlings is briefly discussed.

Item Type:Article
Corporate Creators:Emerging Technologies, Horticulture and Forestry Science
Additional Information:© Crown Copyright.
Keywords:Brassica oleracea; broccoli; Cruciferae; epithiospecifier protein; myrosinase; seedling development; sulphoraphane; sulphoraphane nitrile; terminal alkenyl glucosinolates.
Subjects:Science > Biology > Biochemistry
Plant culture > Seeds. Seed technology
Plant culture > Vegetables
Science > Statistics > Statistical data analysis
Deposited On:02 Feb 2009 05:16
Last Modified:09 Mar 2011 23:23

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