Netherlands Journal of Sea Research 7 : 316-327 (1973) 7th European Symposium on Marine Biology FUNCTIONAL AND MOLECULAR PROPERTIES OF CORPUSCULAR HAEMOGLOBIN FROM THE BLOODWORM GLYCERA GIGANTEA* by R. E. WEBER** (Netherlands Institute for Sea Research, Texel, The Netherlands) CONTENTS I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 316 II. Material and Methods . . . . . . . . . . . . . . . . . . . . . . 317 III. Results and Discussion . . . . . . . . . . . . . . . . . . . . . . 318 A. Whole coelomic fluid . . . . . . . . . . . . . . . . . . . . . 318 B. Hb in solution . . . . . . . . . . . . . . . . . . . . . . . . 319 I. pH effect . . . . . . . . . . . . . . . . . . . . . . . . . 319 2. temperature effect . . . . . . . . . . . . . . . . . . . . . 320 3. concentration effect . . . . . . . . . . . . . . . . . . . . 321 4. ATP effect . . . . . . . . . . . . . . . . . . . . . . . . 321 5. molecular differentiation of Hb and O~-affinity . . . . . . . . 322 IV. General Discussion . . . . . . . . . . . . . . . . . . . . . . . . 324 V. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . 325 VI. References . . . . . . . . . . . . . . . . . . . . . . . . . . . 325 I. INTRODUCTION The ecological niches inhabited by annelid worms are characterized by a great diversity of respiratory conditions. Annelids accordingly exhibit a multiplicity of respiratory adaptations, which are important factors governing their distribution. With regard to "choice" of respiratory pigments, annelids show a similar lack of conservatism, possessing one or more types of pigments with a large range of structural and functional properties. The giant extracellular haemoglobin (Hb) and chlorocruorin molecules (molecu- lar weight 2.7 to 3 × 10~) circulating in a closed blood vascular system are, however, most commonly found. The Hb of the burrowing worm Glycera is in many ways opposite. Glycerids lack a closed blood vascular system and the haemoglobin is * Work was carried out partly at Stazione Zoologica, Naples, Italy, during tenureship of support from the Netherlands' Ministry of Education and Sciences. ** Present address: Zoophysiology Laboratory, University of Aarhus, Denmark.