Structure, function and physiological role of chironomus haemoglobin

1. 1. Some properties of haemoglobin isolated from larval haemolymph of the dipterian family Chironomidae are described in the light of the historical accumulation of our knowledge and recent findings, and on the broad basis of the comparison with haemoglobins from other invertebrates as well as from other chosen vertebrate species. 2. 2. The possible evolutionary connections of these Hbs with the whole family of the haem proteins are demonstrated and it is concluded that almost the same functional properties can be realized by different primary structure of proteins and vice versa. This means that we are able to find some important amino acid blocks or other structural relations characteristic for Hb in other globular proteins. 3. 3. Particular attention is devoted to the relationship between structure and function of these proteins, especially the structural and dynamical conditions of the Bohr effect and a high oxygen affinity. 4. 4. The adaptative significance of haemoglobins to the Chironomids' larvae in mud habitats is discussed in relation to their function. The double role of these Hbs is shown: they can act as a short time oxygen store (connected with the larval respiratory behaviour) and an oxygen transferer (connected with the metamery of the larvae). It is also suggested that they may play an important role in some detoxification processes.