Distribution and respiratory properties of sheep hemoglobins A and B containing the II alphaHis chain.

We recently reported the discovery of a second alpha chain, differing from the common alpha chain by the replacement 113 (or 114) Leucine leads to Histidine, in the hemoglobin of several domestic sheep. The ratio of the common alpha chain, here called alpha Leu, to the variant one, here called II alpha His, was either about 1.8:1 or about 4:1. In this study, the distribution of the II alpha His chain in 217 sheep from 8 domestic breeds was investigated: the II alpha His chain is present in 30% of animals from different breeds. Oxygen equilibrium determination showed no differences in the oxygen affinity, the Bohr effect and the heme-heme interaction of Hb A (alpha 2 beta 2A) and Hb B (alpha 2 beta 2B), each containing one of the three possible alpha chain phenotypes.