Acetylated hemoglobins in feline blood.

The /3 chain amino terminus of one or more hemoglobins in the blood of members of the Felidae family is substituted with an acetyl group. Such acetylated hemoglobins occur together with nonacetylated components in variable proportions in blood of d8erent members of the family. In the lion, tiger, and snow leopard, the acetylated component comprises about 90% of the total hemoglobin; in the serval and caracal it comprises about 70% ; in the cheetah, puma, fishing cat, and jungle cat it comprises about 50% ; and, among domestic cats it comprises 10 to 50%. The occurrence of such p chain-substituted hemoglobins as major components in animal blood is unusual. Except for the minor fetal human component hemoglobin Fr and the minor adult human component hemoglobin Arc, no animal hemoglobin thus far examined has been found to contain amino-blocked p (non ar) chains. Domestic cat hemoglobins with N-acetylated p chain amino termini are insensitive to the modifying influence of organic phosphates on oxygen a@lnity, whereas cat hemoglobins with unsubstituted /3 chain amino termini are sensitive (Taketa, F., Mauk, A. G., and Lessard, J. L., J. Biol. Chem., 246,447l (1971)).