Hemoglobin Rouen (alpha-140 (HC2) Tyr-->His): alteration of the alpha-chain C-terminal region and moderate increase in oxygen affinity.

Hb Rouen (alpha 140(HC2) Tyr-->His) is a moderately high oxygen-affinity variant that was found in coincidence with polycythemia vera in a French patient. This hemoglobin provides an example of an alteration of the C-terminus of the alpha-chain, a region involved in the mechanisms of allosteric regulation. The increase in oxygen-affinity and decrease in cooperativity of this variant is much smaller than that resulting from the same substitution in the beta-chain. This model provides additional evidence for the inequivalence between the alpha- and beta-subunits.