From owner-metabolic-reg@net.bio.net Wed May 31 23:00:00 1995
Path: biosci!FTDETRCK-CCMAIL.ARMY.MIL!dr._margaret_martens
From: dr._margaret_martens@FTDETRCK-CCMAIL.ARMY.MIL
Newsgroups: bionet.metabolic-reg
Subject: Re: ATP/ADP in heart mitochondria
Date: 1 Jun 1995 15:47:53 -0700
Organization: BIOSCI International Newsgroups for Molecular Biology
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     > S.J. Eaton wrote:
     
     > I have a problem in my incubations with heart mitochondria in that
     > I'm doing incubations looking at beta-oxidation flux from palmitate;
     > hence I need ATP (for acyl-CoA synthase) and ADP (for oxidative
     > phosphorylation). This doesn't cause a problem in muscle or liver
     > mitos, but in heart I run out of ATP very quickly in the absence of
     > added substrate; most of it appears to end up in AMP rather than ADP
     > so it doesn't appear to be myofibrillar ATPase, unless it's going
     > via adenylate kinase. I can't think of a way of regenerating ATP,
     > apart from using pyuruvate kinase/PEP, which regenerates ATP, but
     > also eventually yields acetyl-CoA, which could confuse the issue of
     > beta-oxidation itself.
     
     Is there a particular reason for using palmitate as your substrate?  
     Unless you need to know the rate of flux through acyl-CoA synthase, it 
     is much easier to measure the rate of beta-oxidation in isolated 
     mitochondria using palmityl-carnitine as substrate.  If this substrate 
     would suffice for the scientific question you are trying to answer, it 
     would be a way to avoid the problem of ATP utilization/regeneration 
     entirely.
     
     M.E. Martens
     


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