The Function of High Hemoglobin in Large Fish

Abstract

Over the years, a considerable body of evidence has accumulated which shows that fish hemoglobins not only differ from mammalian hemoglobin, but also differ greatly from one another (1,2,3). A large amount of work is involved in characterizing the function of a hemoglobin in detail so relatively few have been studied fully. It seems, however, that there may be three general classes of fish hemoglobins. These are first, the Root effect hemoglobins, in which one chain has a very low affinity for ligand in the T-state, and which show a marked change in affinity with pH (4). Second, and coexistent in the same fish with the Root effect hemoglobins, are the pH invariant and effector independent hemoglobins, studied first by Hashimoto and Matsuura (5) and since examined in great detail here in Rome as trout 1. The third group includes the shark hemoglobins which are cooperative, have chains which are alike in the T-state, and respond only moderately to pH change and to effectors (6,7,8). In looking for an explanation of this functional diversity it is natural to think first of the transport function of hemoglobin in fishes. There is, however, a good deal of evidence to suggest that many fishes can manage quite well without it.