Search results
Results from the WOW.Com Content Network
The mustard oil bomb, formerly known as the glucosinolate–myrosinase complex, is a chemical herbivory defense system found in members of the Brassicaceae (or cabbage family). The mustard oil bomb requires the activation of a common plant secondary metabolite, glucosinolate , by an enzyme, myrosinase .
Whenever sinigrin-containing plant tissue is crushed or otherwise damaged, the enzyme myrosinase degrades sinigrin to a mustard oil (allyl isothiocyanate), which is responsible for the pungent taste of mustard and horseradish. [1] Seeds of white mustard, Sinapis alba, give a less pungent mustard because this species contains a different ...
The pungency of the condiment mustard results when ground mustard seeds are mixed with water, vinegar, or other liquid (or even when chewed). Under these conditions, a chemical reaction between the enzyme myrosinase and a glucosinolate known as sinigrin from the seeds of black mustard ( Brassica nigra ) or brown Indian mustard ( Brassica juncea ...
Ascorbate is a known cofactor of myrosinase, serving as a base catalyst in glucosinolate hydrolysis. [1] [7] For example, myrosinase isolated from daikon (Raphanus sativus) demonstrated an increase in V max from 2.06 μmol/min per mg of protein to 280 μmol/min per mg of protein on the substrate, allyl glucosinolate (sinigrin) when in the presence of 500 μM ascorbate. [4]
In contrast to mustard from black mustard (Brassica nigra) seeds which contain sinigrin, mustard from white mustard seeds has only a weakly pungent taste. [ 1 ] Sinalbin is metabolised to form the mustard oil 4-hydroxybenzyl isothiocyanate by the enzyme myrosinase .
The essence of glucosinolate chemistry is their ability to convert into an isothiocyanate (a "mustard oil") upon hydrolysis of the thioglucoside bond by the enzyme myrosinase. [4] The semisystematic naming of glucosinolates consists of the chemical name of the group "R" in the diagram followed by "glucosinolate", with or without a space.
When these mustard seeds are broken, the enzyme myrosinase is released and acts on a glucosinolate known as sinigrin to give allyl isothiocyanate. [5] This serves the plant as a defense against herbivores; since it is harmful to the plant itself, [citation needed] it is stored in the harmless form of the glucosinolate, separate from the ...
White mustard, Sinapis alba. 4-hydroxybenzyl isothiocyanate occurs as a degradation product of sinalbin or glucosinalbin in white mustard. This compound is broken down as a mustard oil glycoside by myrosinase, releasing the isothiocyanate. The isothiocyanate further decomposes into hydroxybenzyl alcohols with the release of thiocyanates.