Rates of oxygenation and Bohr shift of capillary blood in chick embryos.

Abstract

THE effect of carbon dioxide on the affinity of red blood cells (RBC) for oxygen was first described by Bohr, Hasselbalch and Krogh1. The higher the Pco2 and/or the lower the pH, the lower the O2 affinity. The rate of the affinity change, that is, the Bohr shift, has been measured by several investigators2–4 by abruptly changing the PCo2 of a suspension of RBC using a rapid flow reaction apparatus combined with a PO2 electrode. They showed that the Bohr shift was much slower than the simple oxygenation and deoxygenation rates. While developing a microphotometer technique for kinetic studies of a single RBC in the presence of O2 and CO (refs 5 to 8), we also attempted to determine the rate of the Bohr shift in the capillary blood of chick embryos, and found that the Bohr shift rate was slower than the O2 reaction rates; in particular, in the cooperative reactions of O2 and Bohr shift, the O2 reaction appeared first followed by the Bohr shift.