Linked Life Data

7657629

Source:http://linkedlifedata.com/resource/pubmed/id/7657629

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
35
pubmed:dateCreated
1995-10-4
pubmed:abstractText
Myrosinase (EC 3.2.3.1) is the beta-thioglucosidase enzyme responsible for the hydrolysis of glucosinolates, a group of naturally occurring plant metabolites. The enzyme catalyzes the hydrolysis of these S-glucosides to give D-glucose and an aglycone fragment, which then rearranges to give sulfate and an isothiocyanate. As part of ongoing mechanistic studies on myrosinase, the ability of the enzyme to catalyze transglycosylation reactions has been examined. Enzyme activity and stability were both decreased in the presence of various organic solvents, including simple alcohols, but not sufficiently to prevent reaction taking place. However, in contrast to most other beta-glycosidases, myrosinase did not catalyze transglycosylation reactions either with the alcohols or other suitable glycosyl acceptors. Although a wide range of potential acceptors were investigated, none proved to be effective. Even when appropriately charged side chains were included in the acceptor molecule to mimic the sulfonic acid in the glucosinolate structure, transglycosylation did not take place. The putative enzyme-glycosyl intermediate therefore appears to be unavailable for reaction, possibly because D-glucose is the first product released from the enzyme. The transition state analogue, glucono-delta-lactone, a potent competitive inhibitor of beta-glucosidase, was found to be a poor noncompetitive inhibitor of myrosinase. Myrosinase is specifically activated by ascorbic acid, and it is proposed that the inhibitor is binding at this alternative site.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
270
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
20530-5
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Studies on the mechanism of myrosinase. Investigation of the effect of glycosyl acceptors on enzyme activity.
pubmed:affiliation
School of Chemistry, University of St. Andrews, Fife, United Kingdom.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't