抄録
1. Hemocyanin was found in the hemolymph of Dolahc1la auricularia, an opistho-branchiate gastropod. The hemclymph c_??_stained about one percent by weight of hemocyanin and aimcst all the protein in the. hem_??_lymph was hem_??_cyanin. The copper content of a sample purified by DEAE-cellulose chromatography was 0.228±0.012%, and from this the minimum molecular weight was calculated as 27, 900±1, 500.
2. Analytical ultracentrifugation and electron miclCscopy revealed that the quater-nary structure of Dolahclla-hemocyanin is similar to that of hemocyanin from Busvcon canaliculatunr reported by Fernández-Morán ct al. (l). The molecule of Dolabclla-hemocyanin has a cylindrical structure (diameter, 350 Å; length, 170 Å to 850 Å).
3. The amount of molecular oxygen liberated from oxyhemocyanin i n additif, n of KSCN was determined with a Clark oxygen electrode, and the oxygen binding capacity of Dolabella-hemocyanin was found to be one mole per two g-atoms of copper.
4. The equilibrium between oxygen and hemocyanin was studied by measuring the absorbance change of hemocyanin at 347 mμ or 575 mμ and the change in concen-tration of free molecular oxygen with an oxygen electrode. The oxygen pressure at half saturation and the n-value in Hill's equation were found to be 6.2 mmHg and 1.9, respectively.
