From owner-metabolic-reg@net.bio.net Fri Jun 18 12:34:00 1999 Path: biosci!news.stanford.edu!newsfeed.stanford.edu!newsfeed.berkeley.edu!dispose.news.demon.net!demon!newsfeed.nacamar.de!newsfeed.nacamar.de!nntp.news.xara.net!xara.net!server6.netnews.ja.net!server4.netnews.ja.net!server2.netnews.ja.net!hgmp.mrc.ac.uk!biosci From: JHSH@land.sun.ac.za ("Jannie Hofmeyr") Newsgroups: bionet.metabolic-reg Subject: Re: BSA vs. MCA Date: 18 Jun 1999 14:28:54 +0100 Organization: Stellenbosch University Message-ID: References: <9906180854.ZM27316@valiant.niehs.nih.gov> NNTP-Posting-Host: mercury.hgmp.mrc.ac.uk Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Trace: niobium.hgmp.mrc.ac.uk 929712535 17511 193.62.192.80 (18 Jun 1999 13:28:55 GMT) X-Complaints-To: news@hgmp.mrc.ac.uk NNTP-Posting-Date: 18 Jun 1999 13:28:55 GMT X-Received: from mail.sun.ac.za (mail.sun.ac.za [146.232.128.1]) by hgmp.mrc.ac.uk (8.9.3/8.9.3) with ESMTP id OAA29488 for ; Fri, 18 Jun 1999 14:28:38 +0100 (BST) X-Received: from land.sun.ac.za ([146.232.216.2]) by mail.sun.ac.za with esmtp (Exim 2.10 #1) id 10uygc-0006u1-00 for btk-mca@hgmp.mrc.ac.uk; Fri, 18 Jun 1999 15:28:02 +0200 X-Received: from SUN_LAND/SpoolDir by land.sun.ac.za (Mercury 1.44); 18 Jun 99 15:27:32 +0200 X-Received: from SpoolDir by SUN_LAND (Mercury 1.44); 18 Jun 99 15:27:27 +0200 X-To: btk-mca@hgmp.mrc.ac.uk X-Reply-to: jhsh@maties.sun.ac.za X-Priority: normal X-In-reply-to: <9906180854.ZM27316@valiant.niehs.nih.gov> X-Mailer: Pegasus Mail for Win32 (v3.11) Lines: 34 Dear Michael You wrote > 5. Which method you choose to use depends on what information is > available and what question you are asking. If you only have > steady-state or time-course concentration data, then you probably will use > BSA. MCA requires detailed kinetic information to identify the true rate > laws and the numerical values of the kinetic parameters. If you just wish > to estimate error envelopes for a simulation, any method of sensitivity > analysis will do. The more realistic the mathematical representation, the > deeper is the possible molecular-level insight. and Henrik promptly turns in his grave. The whole idea of MCA is that it needs **no** local kinetic information for its application, only the ability to manipulate parameters and measure steady-state variable such as fluxes and intermediate concentrations. With co-response analysis this ideal became reality (also to a more limited extent with the top-down approach). One should distinguish the experimental use of MCA from numerical simulation where control coefficients can also be calculated. For numerical simulation the question becomes one of using power laws (a la BST) versus true rate laws where detailed kinetic information is needed. Best regards Jannie Prof. Jannie Hofmeyr Tel: +27 21 808 3039 Dept. of Biochemistry Fax: +27 21 808 3022 University of Stellenbosch e-mail: jhsh@maties.sun.ac.za Private Bag X1 Matieland 7602 Stellenbosch South Africa --- .