Hemocyanins are large respiratory proteins of arthropods and mollusks, which bind oxygen with very high cooperativity. Here, we investigated the relationship between oxygen binding and structural changes of the 24-mer tarantula hemocyanin. Oxygen binding of the hemocyanin was detected following the fluorescence intensity of the intrinsic tryptophans. Under the same conditions, structural change...

Hemocyanin in the hemolymph of the horseshoe crab, Limulus polyphemus L., is a high-molecular-weight copper protein which binds oxygen cooperatively and shows a higher oxygen affinity at pH 7 than at pH 9. Treatment with EDTA (ethylenediaminetetra-acetate) disaggregates the hemocyanin molecules and abolishes both the reverse Bohr effect and cooperative oxygen binding. Chloride ions interact wit...

Chemical—spectroscopic studies of the coupled bimuclear copper active site are presented which interpret the unique spectral features associated with oxyhemocyamim. These features are them used to generate a 'spectroscopically effective' model for this active site. First the met apo [Cu(II) — I and half met [Cu(II)Cu(I)J derivatives are spectro— scopically compared; they demonstrate that exogen...

Since the classic observations of Bert (1867) and Fredericq (1878) called attention to the significance of the copper-protein compound, hemocyanin, subsequent investigators have concerned themselves with two questions of biological importance.’ What is the general nature of the union whereby hemocyanin may function as an oxygen carrier in the blood? Do the hemocyanins of various groups of anima...

Hemocyanins are large multi-subunit copper proteins that transport oxygen in many arthropods and mollusts. The amino acid sequence of subunit a of Panulirus interruptus hemocyanin (657 residues) has been completed and fitted to the electron-density map (3.2 A resolution). Comparison of amino acid sequence data for several different hemocyanin subunits of arthropod species indicated that the gen...

Horseshoe crabs have been identified as one of the marine species that contribute greatly to scientific advances especially in haematological studies. Besides the haemocytes of these creatures, they are also well known for their protein contents in the perivitelline fluid (PVF). Due to this, over the years, there has been increasing interests in the scientific community to explore the function ...