Re: specific amino acid restriction does the same thing as calorie restriction?

From: R. Coyote (coyyote@hotmail.com)
Date: Sat Apr 19 2003 - 13:02:50 MDT

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    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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