Search Mailing List Archives
dirigent proteins
Pankaj Jaiswal
pj37 at cornell.edu
Tue Jul 2 07:30:04 PDT 2002
Hi,
What i figured out about this enzyme is
"Dirigent protein in the presence of an oxidase or one electron oxidant, effects
stereoselective bimolecular phenoxy radical coupling in vitro. Itself lacking a
catalytically active (oxidative) center, its mechanism of action is presumed to
involve capture of E-coniferyl alcohol-derived free-radical intermediates, with
consequent stereoselective coupling to give (+)-pinoresinol." PMID: 8994027
definition: Lacking catalytic active site, the protein in the presence of an
oxidase or one electron oxidant, effects stereoselective bimolecular phenoxy
radical coupling, thus becoming a part of holozyme. Best characterised as a
function during lignan biosynthesis.
term name: stereoselective coupling (as function)
synonym:dirigent protein
instance of "enzyme regulator" (GO:0030234) as Michael suggested
First I thought about it as a isomerase/racemase, but since its not responsible
for this kind of an activity it can go as an enzyme regulator. Though its
clearly a part of oxidase carrying out the reaction converting E-coniferyl
alcohol to a(+)-pinoresinol
"Michael Ashburner (Genetics)" wrote:
>
> Sorry to be so long in replying to this:
>
> I think that we need a new function term for dirigent proteins. I have done
> some reading and suggest this new term:
>
> guiding stereospecific synthesis ; GO:??????? ; synonym:dirigent protein
>
> definition: The orientation of free radical substrates in such a way that
> only a particular stereoisomer is synthesised by an enzyme. Best characterised
> as a function during lignan biosynthesis.
>
> It is not clear where this should go, but I suggest that it could be a
> direct child of "enzyme regulator" (GO:0030234) whose definition is
> "Modulates the activity of an enzyme."
>
> Feedback please.
>
> Michael
>
> > From owner-gofriends at genome.stanford.edu Thu Jun 13 18:51:43 2002
> > Envelope-to: ma11 at gen.cam.ac.uk
> > Delivery-date: Thu, 13 Jun 2002 18:51:43 +0100
> > X-Authentication-Warning: alberich.Stanford.EDU: majordom set sender to owner-gofriends at genome-mail.stanford.edu using -f
> > From: "Hannick, Linda" <lhannick at tigr.org>
> > To: geneontology-term-request at lists.sourceforge.net,
> > "Smith, Roger"
> > <rsmith at tigr.org>
> > Cc: Midori A Harris <midori at genome.Stanford.EDU>, gofriend at genome.Stanford.EDU
> > Date: Thu, 13 Jun 2002 13:50:08 -0400
> > MIME-Version: 1.0
> > X-Mailer: Internet Mail Service (5.5.2653.19)
> > Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C21302.C1E0C230"
> > Sender: owner-gofriends at genome.stanford.edu
> > Content-Length: 12447
> >
> > We are currently looking at dirigent proteins, and are not experts in lignan
> > biosynthesis. Maybe someone with more expertise in this field can help us
> > come up with a GO term to accurately describe the function of this protein
> > and where it fits in the DAG (GO:0009807 accurately describes the process
> > that it is involved in).
> >
> > Dirigent proteins, in the presence of an oxidase or one electron oxidant,
> > affect stereoselective biomolecular phenoxy radical coupling (See Gang et
> > al. (1999) Chem Biol 6, 143-151). They do not have a catalytically active
> > (oxidative) center, but they orient free radical substrates in such a way
> > that random coupling cannot occur, and only the 8-8'-coupled intermediate
> > (+)-pinoresinol is formed. Any suggestions on where this should be added?
> >
> > Thanks
> > Roger Smith
> > The Institute for Genomic Research
> > Bioinformatics Analyst
> > rsmith at tigr.org
> >
> >
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > Linda I. Hannick, Ph.D.
> > The Institute for Genomic Research
> > Bioinformatics Analyst
> > 9712 Medical Center Drive
> > Rockville MD 20850
> > ~~~~~~~~~~~~~~~~~~~~
> >
> > 301-838-5857 voice
> > 301-838-0208 fax
> > lhannick at tigr.org
> >
>
> --
> This message is from the GOFriends moderated mailing list. A list of public
> announcements and discussion of the Gene Ontology (GO) project.
> Problems with the list? E-mail: owner-gofriends at geneontology.org
> Subscribing send "subscribe" to gofriends-request at geneontology.org
> Unsubscribing send "unsubscribe" to gofriends-request at geneontology.org
> Web: http://www.geneontology.org/
--
******************************************
Pankaj Jaiswal, Ph.D.
Postdoctoral Associate
Dept. of Plant Breeding
Cornell University
Ithaca, NY-14853, USA
Tel:+1-607-255-3103 / Fax:+1-607-255-6683
E mail: pj37 at cornell.edu
http://www.gramene.org
******************************************
--
This message is from the GOFriends moderated mailing list. A list of public
announcements and discussion of the Gene Ontology (GO) project.
Problems with the list? E-mail: owner-gofriends at geneontology.org
Subscribing send "subscribe" to gofriends-request at geneontology.org
Unsubscribing send "unsubscribe" to gofriends-request at geneontology.org
Web: http://www.geneontology.org/
More information about the go-friends
mailing list