Hemoglobin and myoglobin embedded in dry poly(vinyl alcohol) film for X-ray absorption studies

Solid hemoprotein samples are prepared by embedding proteins in thin poly(vinyl alcohol) films. These film samples have several unique qualities: in the solid poly(vinyl alcohol) matrix, hemoproteins have the same properties as in frozen buffer solution (proven by optical absorption, ligand recombination kinetics and EXAFS); they are very stable, easy to store and resistant to radiation; damage; protein concentration can be as high as 15 mM; light transparency is as good as liquid solution samples; and they can be made as thin as 20 microns, so that 100% photolysis across a film, even with a high protein concentration, is easily achievable. The film samples are ideal for X-ray studies of optically illuminated hemoproteins.