In article <32603228.1811 at umslvma.umsl.edu>, Milvern K Miller wrote:
>>It is somewhat interesting that my statement about drinking deionized
>water has generated such a response. With regard to D20, I think I
>rember reading once in Encyclopedia Brittanica (my old 1971 edition)
>that D20 will have the interesting effect of slowing reactions down
>within a cell when there is a large amount of D20 present (on the order
>of 5% or more). I heard that the reason this is so is that although
>Deuturium is electronically identical to Hydrogen, its extra weight will
>cause reactants to move more slowly as each reaction occurs, either
>because of hindrance of other molecules, or because of its being
>incorporated into the organic molecules of the cell and slowing those
>molecules down by increased weight. I may be mistaken but I think that
>is what I heard.
It is called the 'kinetic isotope effect' and I think the effect is due
to the larger mass of D compared to H, as you mention. It's a measurable
effect and occasionally is a concern, but rarely do you see so much D2O in
your H2O that it's worth worrying about.
I noticed this is xposted to alt.beer. Anybody brewing beer using DI water?
-- David Konerding --
Graduate Group in Biophysics, Box 0446
University of California
San Francisco, CA 94143
email: dek at cgl.ucsf.edu WWW:http://picasso.ucsf.edu/~dek