Temperature adaptation at the hemoglobin level in Carassius auratus

Abstract

1. Goldfish ( Carassius auratus) were acclimatized at 4, 21 and 37°C for a minimum of 1 month to study the respiratory adaptation at the level of the hemoglobin. 2. Goldfish present a single molecular form of Hb which does not change during the adaptation. 3. The acclimatization produces wide fluctuations in the oxygen dissociation curves of Hb determined on the crude hemolysates. The fluctuations are determined by the presence of a cofactor different from the organic phosphates. The affinity for the oxygen of the purified Hb remains unchanged during the acclimatization. 4. The cofactor regulates the size of the Bohr effect and diminishes the temperature dependence of the oxigenation reaction. 5. The effect of the cofactor is largely species aspecific.