Oriented Crystallization of Urea in Membranes
Inner egg shell membrane was soaked in 2 M urea solution and dried. Cu Kα X-rays directed perpendular to the membrane yielded an unsymmetrical diffraction pattern with urea 110, 111, 102, 210 and 211 planes diffracting to the right and urea 101, 200 and 201 planes diffracting to the left. The urea appears to be hydrogen-bonded diagonally between the lamellae of β-keratin at an angle of 33.5° to the 6.68 Å b-axis (fiber axis) of the parallel pleated sheet structure, shortening the half-axis lengths in the a direction from 4.73 Å to 4.41 Å. Similar results were obtained with formalinized dog mesentery. Keratinous outer egg shell membrane, formalinized collagenous dog renal capsule, formalinized collagenous pheasant pericardium, and formalinized callogenous human arachnoid yielded symmetrically oriented urea layer lines. Formalinized dog renal fascia and pleura yielded random urea lines.
KeywordsUrea Solution Urea Molecule Collagen Collagen Renal Fascia Pleated Sheet
Unable to display preview. Download preview PDF.