Changes in the membrane proteins of blood cells in the course of embryonal megaloerythropoiesis in relation to hemoglobin maturation

: Membrane proteins in circulating blood cells were examined in chick embryos on the 4th, 5th, 6th, 7th and 10th incubation day, in chicks immediately after hatching, and in adult birds. Haemoglobin electrophoresis patterns were determined on cellulose acetate after solubilisation with urea, and in gradient of pH and concentration on acrylamide gels after solubilisation in SDS. Amino acids and other amino compounds were also determined after acid hydrolysis and resin chromatography. Haemoglobin patterns were similar to those displayed by the membrane proteins. The latter, however, changed more slowly.