Energetic costs of protein synthesis do not differ between red- and white-blooded Antarctic notothenioid fishes.

摘要: Antarctic icefishes (Family Channichthyidae) within the suborder Notothenioidei lack oxygen-binding protein hemoglobin (Hb), and six of 16 species myoglobin (Mb) in heart ventricle. As iron-centered proteins, Hb Mb can promote formation reactive oxygen (ROS) that damage biological macromolecules. Consistent with this, our previous studies have shown lower levels oxidized proteins lipids oxidative muscle compared to red-blooded notothenioids. Because are usually degraded by 20S proteasome must be resynthesized, we hypothesized rates synthesis would notothenioids, thereby reducing energetic costs conferring a benefit loss Mb. Rates were quantified hearts, fraction consumption devoted was measured isolated hepatocytes cardiomyocytes notothenioids differing expression cardiac Neither nor differed among species, suggesting do not degrade replace oxidatively modified at higher rate but rather, persist proteins.