Post-synthetic modification in vivo of the major hemoglobin β chain in the rat

Rat hemoglobins are unusually heterogeneous among mammals. This heterogeneity provides multiple opportunities for asynchronies in synthesis and degradation. We have examined rat hemoglobin turnover after an intravenous injection of 2-^-14C-glycine. After analyzing incorporation into the seven nonallelic globin chains of adult rats, we found the percentage of the major β chain decreases over the red cell lifespan while the percentage of one of the minor β chains increases. This suggests that a post-synthetic mdification event converts a portion of the latter into the former.