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Influence of pH and type of myrosinase complex on the products obtained in the myrosinase catalysed hydrolysis of glucosinolates – a MECC study

Bellostas, Natalia; Sørensen, Jens C. and Sørensen, Hilmer (2007) Influence of pH and type of myrosinase complex on the products obtained in the myrosinase catalysed hydrolysis of glucosinolates – a MECC study. Paper at: 12th international Rapeseed Conferece, Wuhan, China, 26-29 March 2007.

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Summary

Environmental conditions, e.g. pH and the presence of Fe2+ are well known factors that influence the product profile of the myrosinase catalysed hydrolysis of glucosinolates. Depending on the plant genera, the species and tissue of origin myrosinase isoenzymes (thioglucohydrolase EC 3.2.1.147) have different characteristics in terms of MW, subunit composition and pI. However, the influence of these parameters on the outcome of glucosinolate hydrolysis has not been traditionally studied, which hinders the full exploitation of the catalytic potential of these enzymes. In the present experiments the effect of myrosinase type on the products obtained in the hydrolysis of glucosibarin was studied by MECC using two B. carinata myrosinase preparations differing on their affinity to the Con A material, Con A 1 (first eluting fractions) and Con A 2 (last eluting fractions). At pH 3 Con A 1 isoenzymes were more active than Con A 2 isoenzymes. At pH 5 and 6.5 Con A 1 isoenzymes produced oxazolidine-2-thione to a higher extent than Con A 2 isoenzymes. The production of nitriles by Con A 1 isoenzymes was not influenced by pH and at pH 5 and 6.5 the amount of nitrile produced by Con A 1 isoenzymes was lower than that produced by Con A 2 isoenzymes. Formation of nitriles requires the presence of two redox equivalents which leads to the release of the sulphur atom from the aglucone. Isothiocyanates and nitriles differ in their bioactivity towards different targets; therefore the possibility for directing the glucosinolate hydrolysis towards the desired compound in a particular situation is of great relevance.


EPrint Type:Conference paper, poster, etc.
Type of presentation:Paper
Subjects: Crop husbandry > Crop health, quality, protection
Food systems > Food security, food quality and human health
Research affiliation: Denmark > KU-LIFE - Faculty of Life Sciences
Denmark > SOAR - Research School for Organic Agriculture and Food Systems
Deposited By: Bellostas Muguerza, Natalia
ID Code:11399
Deposited On:01 Oct 2007
Last Modified:12 Apr 2010 07:35
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

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