Summary
Two species of fish hemoglobin from Amazon river were analized in order to establish the relationship between their molecular and physiological properties as well as their interactions with other molecules and ions. The species were different regarding respiration, activity and habitat. The polyacrylamide eletrophoresis pattern of aruanã hemoglobin showed only one component and pronounced Bohr and Root effect and the Hill coefficient showed significant variation with the pH in the presence or not of 10-3M ATP. The total hemolisate of acari-bodó presented not Bohr effect nevertheless the four isolated components showed different functional properties thus the Hbl component, showed small reverse Bohr effect that becomes normal in the presence of 10-3M ATP at low pH. The other three components presented normal Bohr effect and ATP does not change this effect. These results cleary show the capacity of molecular adaptation of fish hemoglobin to adapt to both the metabolic requirements and environment variations of the animals.