From owner-metabolic-reg@net.bio.net Fri Oct 22 13:44:00 1999 Path: biosci!newsfeed.stanford.edu!newsfeed.berkeley.edu!news-out.uswest.net!news.uswest.net!not-for-mail Newsgroups: bionet.metabolic-reg Subject: Re: 'key' concepts From: pjm@ncgr.org (Pedro Mendes) Organization: Natl. Center for Genome Resources X-Newsreader: WinVN 0.99.9 (Released Version) (alpha 32bit) References: <7r58l9$t3l$1@dyfi.aber.ac.uk> MIME-Version: 1.0 Content-Type: Text/Plain; charset=US-ASCII Lines: 58 Message-ID: Date: Fri, 22 Oct 1999 14:37:37 GMT NNTP-Posting-Host: 216.161.34.129 X-Trace: news.uswest.net 940603057 216.161.34.129 (Fri, 22 Oct 1999 09:37:37 CDT) NNTP-Posting-Date: Fri, 22 Oct 1999 09:37:37 CDT In article , chipman@bgumail.bgu.ac.il says... > >[...] > 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"]. Or anything else for that matter. Not many metabolites can be defined in that way at all... in fact that definition is rather difficult to defend since there is alwyas the possibility that a metabolite we thought is only involved in one pathway may well be involved in another yet unknown (and, remember the 50% or more genes in all fully sequenced genomes are of unknown function) >"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." Again, "Key" used in this way is really a useless word, since then all enzymes are key... Remove any enzyme out of a pathway and it will no longer function. In that sense all are key. If "Key" means "my pet enzyme" then it is such a non-scientific concept that we should not even be discussing it. >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. We don't, we don't even use it. By the way, many (MANY) experimentalists (if that means anything) have come to the same conclusions the hard way. Look for example the work of Heinish: Heinisch, J. (1986) Construction and physiological characterization of mutants disrupted in the phosphofructokinase genes of Saccharomyces cerevisiae. Current Genetics 11, 227-234. >Could it be that there is a reason why molecular biologists and >others ignore what metabolic theorists might have to offer? This is not true, David Fell's book has an extensive bibliography on experimental approaches to metabolic control analysis. Many of the people who regularly post here (who you probably would call theoreticians) spend more time in the lab than at their keyboard... (not me, though). There is currently a great interest by the pharmaceutical (and biotechnology in general) industry in MCA. The bottom line is that the use of the word "Key" is either so wrong, unpecific or unscientific that it makes it useless and misleading. Pedro Mendes National Center for Genome Resources, 1800-A, Old Pecos Trail, Santa Fe, NM 87505, USA http://www.ncgr.org .