From: R. Coyote (coyyote@hotmail.com)
Date: Sat Apr 19 2003 - 13:02:50 MDT
I'm wondering if proteolytic enzymes such as papain or bromelain would cause
more protein recycling
----- Original Message -----
From: "Robert J. Bradbury" <bradbury@aeiveos.com>
To: <extropians@extropy.org>
Sent: Saturday, April 19, 2003 6:24 AM
Subject: Re: specific amino acid restriction does the same thing as calorie
restriction?
>
> On Sat, 19 Apr 2003, Reason wrote:
>
> > It seems to be claiming that if you cut out 1 1/2 amino acids of the
normal
> > spread of amino acids in rat food, you get long-lived rats. Can the
people
> > on the list who are way far more knowledgable than me about such things
> > weigh in with whys and wherefores?
>
> If you dig really deep into the literature (and I mean *really* deep)
> you will find that restriction of some of the essential amino acids
> (i.e. those that cannot be synthesized) cause an up-regulation of
> protein recycling. As I recall there are multiple pathways that
> may be involved (which makes sense from a biochemical standpoint).
> The effect may also have some species specificity because I doubt
> that species are likely to encounter the same amino acid shortages
> given the variety of diets (of say mice/rats vs. humans).
>
> The working hypothesis that others (and I) have had is that if
> you increase protein recycling one gets a greater ratio of
> "new" proteins vs. "old" proteins. The new proteins are less
> damaged than the old proteins (from say oxidative or deamidation
> damage) and thus function more reliably/efficiently. An increase in
> the protein turnover rate may also cause proteins to be broken
> down before they accumulate sufficient damage that the normal
> recycling mechanisms will not work and they end up accumulating
> as lipofuscin.
>
> For more information you want to do a PubMed search on
> "Cuervo AM" and/or "Dice JF".
>
> Its also starting to become clear that there are "molecular clocks"
> that determine the protein recycling rate -- see:
> http://www.deamidation.org/
>
> It seems highly unlikely (at least to me) that the clock timings are
> setup optimally to recycle proteins as the protein recycling
> machinery becomes less efficient due to it being blocked by
> materials it is less able to recycle (e.g. lipofuscin).
> This would be a classic case of antagonistic pleiotropy --
> i.e. you don't want to recycle proteins too fast at a young
> age because it wastes energy but when you get older and the
> recycling machinery is less efficient the timings are too
> slow to maintain the majority of proteins in an optimal state.
>
> Is this "common knowledge" within the aging research community?
> I can only state that I was at a lecture by Steve Austad, who
> I consider to be a leading aging researcher, last week and asked
> him whether he was aware of the molecular clock data.
> The answer was "No".
>
> I suppose that is one reason why one asks the ExI list...
>
> Robert
>
>
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