Myrosinases

Glucobrassicin is a mustard oil glucoside found in various Bras-sica spp. (50). 3-Indoleacetonitrile (IAN) is released from glucobrassicin by the action of the enzyme myrosinase at pH 4.0. How-... 

Fig. 4.1 Sinigrin is an aliphatic glucosinolate that occurs at significant levels in the human diet, notably in mustard and Brussels sprouts. When brought into contact with myrosinase, derived either from plant cells or from colonic bacteria, it is broken down to yield a variety of products including the acrid, volatile, biologically active compoimd...

Ingested glucosinolates Breakdown by plant myrosinase 0 Breakdown by bacterial myrosinase 0 Faeces... 

Cells exposed to myrosinase treated parent glucosinolate at neutral pH. 

LUDiKHUYZE L, ooMS v, WEEMAES 0 and HENDRicKSE M (1999) Kuietic study of the irreversible thermal and pressure inactivation of myrosinase from broccoli (Brassica oleracea L. cv. italica) , J Agric Food Chem, 47 1794-800. 

LUDIKHUYZE L, RODRIGO L and HENDRICKSE M (2000) The activity of myrosinase from broccoli (Brassica oleracea L.cv. Italica) influence of intrinsic and extrinsic factors J Food Protect, 63 400-403. 

NASTRUZZI C, CORTESI R, ESPOSITO E, MENEGATTI E, LEONI O, lORI R and PALMIERI S (2000) In vitro antiproliferative activity of isothiocyanates and nitriles generated hy myrosinase-mediated hydrolysis of glucosinolates from seeds of cruciferous vegetables , JAgric Food Chem, 48 3572-5. 

In general, one would expect that every enzyme will be released close to the roots either by roots or by microbes and eventually will be immobilized in rhizo.sphere soil. If a given enzyme activity has not yet been measured in rhizosphere soil, this is likely more due to the lack of specifically devoted studies or suitable methods than to a real absence. For example, a recent study has first developed an assay for myrosinase in soil and, second, has hypothesized the... 

Buskov S, Serra B, Rosa E, Sorensen H and Sorensen J C (2002), Effects of intact glucosinolates and products produced from glucosinolates in myrosinase-catalyzed hydrolysis on the potato cyst nematode (Globodera rostochiensis Cv Woll) , J Agric Food Chem, 50, 690-695. 

Figure 13.1 Degradation of glucosinolates. Hydrolysis is catalyzed by myrosinases and gives rise to different degradation products dependent on the structure of the glucosinolate side chain and the hydrolysis conditions. (I) isothiocyanates, the major product at pH >7 (II) nitriles, the major product at pH <4 (ID) thiocyanates, produced from 2-propenyl-, benzyl-, and 4-methylthiobutylglucosinolates (IV) oxazolidine-2-thiones, produced from glucosinolates with P-hydroxylated side chains, (V) epithionitriles, produced in the presence of epithiospecifier proteins.

RASK, L., ANDREASSON, E., EKBOM, B ERIKSSON, S., PONTOPPIDAN, B., MEIJER, J., Myrosinase gene family evolution and herbivore defense in Brassicaceae, Plant Mol. Biol., 2000,42, 93-113. 

BURMEISTER, W.P., COTLAZ, S, DRIGUEZ, H, LORI, R., PALMIERI, S., HENRISSAT, B., The crystal structures of Sinapis alba myrosinase and a covalent glycosyl-enzyme intermediate provide insights into the substrate recognition and active-site machinery of an. S -glycosidase, Structure, 1997, 5, 663-675. 

Myrosinase has thioglucosidase activity. The myrosinase-mediated degradation of glucolimnanthin yields an intermediate aglycone that rearranges to form... 

Meadowfoam seeds differ from the seed meal in that seeds, even after years of storage, contain active myrosinase whereas the meal does not. In order to prevent myrosinase-mediated degradation of glucohmnanthin during extraction, one could inactivate myrosinase by applying heat or by choosing a solvent in which myrosinase does not exhibit activity. We have found that heating seeds at temperatures... 

As pro-bioherbicides, glucosinolates can be utilized to control weeds but the success depends on their conversion into active principles. Agricultural use of untreated seed meal may elicit varying degrees of weed control because environmental factors determine the extent of glucosinolate bio-activation in the field [39, 42 5]. Our approach to ferment seed meal using myrosinase (and possibly other enzymes) in... 

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