The structure of a-Glucose-1-Phosphate, the Cori Ester, in
the form of its dipotassium salt dihydrate has "been determined and
the structure compared with those of analogous compounds.
The methods used were hased mainly on the three-dimensional
vector function, partly using the isomorphous diammonium-Glucose1-Pho8phate dihydrate. The information derived from the short
intramolecular vectors appearing round the origin of the 'sharpened'
vector map was found to he particularly valuable. Direct methods
of sign determination were also examined and found to he potentially
Refinement was carried out initially by Fourier methods and
finally by the method of Least Squares, all such calculations being
done on the D.E.U.C.E. Computer of Glasgow University.
The molecular structure is confirmed as being that found by
purely chemical methods. The Glucose-1-Phosphate molecule possesses
the long (1.59 °A) phosphorous-ester oxygen "bond which is found in
other sugar phosphate structures and which seems to he characteristic
of this class of compound. In addition, the bond from carbon (1)
to the ester oxygen is shorter (1.37 °A) than average. The angle at
this oxygen, 124°, is rather wide.
The crystal structure itself is held together by a comprehensive
system of non-covalent bonds linking the cations, the free oxygens of
the phosphate group, the hydroxyl groups of the sugar ring, and the
water molecules. The completeness of this system explains the
comparative hardness of the crystal and its lack of any preferred