e de Hevesy gained
some insight into the surprising mobility of phosphates in organisms: "A
phosphate radical taken up with the food may first participate in the
phosphorylation of glucose in the intestinal mucose, soon afterwards
pass into the circulation as free phosphate, enter a red corpuscle,
become incorporated with an adenosine triphosphoric-acid molecule,
participate in a glycolytic process going on in the corpuscle, return to
circulation, penetrate into the liver cells, participate in the
formation of a phosphatide molecule, after a short interval enter the
circulation in this form, penetrate into the spleen, and leave this
organ after some time as a constituent of a lymphocyte. We may meet the
phosphate radical again as a constituent of the plasma, from which it
may find its way into the skeleton."[38] Much has been added in the last
30 years to complete this picture in many details and to extend it to
other biochemical processes, including even the changes of the pigments
in the retina in the visual process, or in the conversion of chemical
energy to light by bacteria and insects.

Medicines and Poisons

In the delicate balance of these processes, disturbances may occur which
can be remedied by specific phosphate-containing medicines. Thus,
adenosine phosphate has been recommended in cases of angina pectoris
and marketed under trade names like sarkolyt, or in compounds named
angiolysine. A considerable number of physiologically active organic
phosphates can be found in the patent literature.[39] Yeast itself is
considered to be a valuable food additive.

On the other hand, there are phosphate compounds that act as poisons.
One group of such compounds was discovered in 1929 by W. Lange, who
wrote: "Of interest is the strong action of mono-fluorophosphate esters
on the human body--the effect is produced by very small quantities."[40]
Diisopropyl fluorophosphate has since become a potential agent for
chemical warfare. It inactivates an enzyme which controls the
transmission of nerve impulses to muscle, acetylcholine esterase.

Organic esters of phosphoric acids are used as insecticides. The
hexa-ethylester of tetraphosphoric acid, prepared by Gerhard Schrader by
heating triethylphosphate with phosphorus oxychloride,[41] actually
contains tetraethylpyrophosphate (TEPP) among others. Bayer's Dipterex,
the dimethyl ester of 2,2,2-trichloro-1-hydroxyethyl-phosphonate, has
been modified to dimethyl-2,2-di