From owner-metabolic-reg@net.bio.net Fri Oct 22 11:46:00 1999 Path: biosci!newshost.lanl.gov!logbridge.uoregon.edu!dispose.news.demon.net!demon!colt.net!news0.de.colt.net!news-fra1.dfn.de!fu-berlin.de!server1.netnews.ja.net!pegasus.csx.cam.ac.uk!hgmp.mrc.ac.uk!biosci From: chipman@bgumail.bgu.ac.il (David Chipman) Newsgroups: bionet.metabolic-reg Subject: Re: 'key' concepts Date: 22 Oct 1999 13:39:13 +0100 Organization: MRC Human Genome Mapping Project Resource Centre Message-ID: References: <7r58l9$t3l$1@dyfi.aber.ac.uk> NNTP-Posting-Host: mercury.hgmp.mrc.ac.uk Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Trace: niobium.hgmp.mrc.ac.uk 940595953 7218 193.62.192.80 (22 Oct 1999 12:39:13 GMT) X-Complaints-To: news@hgmp.mrc.ac.uk NNTP-Posting-Date: 22 Oct 1999 12:39:13 GMT X-Received: from bgumail.bgu.ac.il (bgumail.bgu.ac.il [132.72.143.1]) by hgmp.mrc.ac.uk (8.9.3/8.9.3) with ESMTP id NAA24655 for ; Fri, 22 Oct 1999 13:39:09 +0100 (BST) X-Received: from localhost (chipman@localhost) by bgumail.bgu.ac.il (8.8.8/8.8.8) with ESMTP id OAA18657; Fri, 22 Oct 1999 14:39:12 +0200 (IST) X-To: Douglas Kell X-cc: btk-mca@hgmp.mrc.ac.uk X-In-Reply-To: <7r58l9$t3l$1@dyfi.aber.ac.uk> Lines: 53 I would like to suggest some self-examination by some of the participants in this news group. I followed with a jaundiced eye (but obviously not jaundiced enough to drop everything and write a reply at once) the exchange which began with: On Wed, 8 Sep 1999, Douglas Kell wrote: > Followers of this newsgroup are used, of course, to casting scorn on the > concept of a 'key' ENZYME with respect to flux control and its > inhibition/stimulation. Collectors might therefore interested in the > following phrase from the abstract of a paper (actually it's a very good > paper, of course....) > > Inhibitors of the Nonmevalonate Pathway of Isoprenoid Biosynthesis as > Antimalarial Drugs, by Hassan Jomaa et mult. al., Science , vol 285, 1573ff: > (1999, Sept 3rd issue) > > "This pathway includes 1-deoxy-D-xylulose 5-phosphate (DOXP) as a key > metabolite". I think it is very clear and very obvious what is meant by "a key metabolite in this pathway": This is one of the metabolites which DEFINES in the conceptual sense the "nonmevalonate pathway" in question. It is not a metabolite on the "conventional" pathway, and its involvement in isoprenoid synthesis seems, for the moment, to be its raison d'etre, if you will. [Parenthetically, I don't see how the tools of any metabolic control theory could be of help in testing a statement such as "involvement in pathway X is the sole important function of metabolite Y"]. "Key" is very often used in this sense, with regard to enzymes, metabolites, control elements, etc.: "This or that is "Key", because to understand what the author believes is interesting or important about the subject at hand, one must take it into consideration." I don't think it is wise for one school of theoreticians to lay absolute claim to the legitimate use of terms [e.g., "key"] that they didn't invent. Such an approach (and the arrogant disdain it might imply) only hampers communication among disciplines. Could it be that there is a reason why molecular biologists and others ignore what metabolic theorists might have to offer? David Chipman - - - - - - - - - - - - - - - - - - David M. Chipman Professor, Biochemistry Chair, Department of Life Sciences Ben-Gurion University POB 653, Beer-Sheva 84105 ISRAEL Tel: {+972}-7-647 2635 (Department) or 2646 (Lab) Fax: {+972}-7-647 2992 Email: chipman@bgumail.bgu.ac.il --- .