Hemocyanin from Dolabella auricularia
IV. Dissociation by DEAE-Cellulose
1972 Volume 72 Issue 1 Pages 29-37
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1972 Volume 72 Issue 1 Pages 29-37
It was shown that hemocyanin from a gastropod, Dolabella auricularia was dissociated into smaller units by passing through a DEAE-cellulose column. The sedimentation coefficient of DEAE-dissociated hemocyanin fraction I, which was not adsorbed by the ion exchanger, was 15 to 19 S. Fraction I was converted by prolonged contact with the ion exchanger into fraction II, which was adsorbed by DEAE-cellulose. In fraction II, two components with sedimentation coefficients of 4 and 7 S were observed. By means of gel filtration the molecular weights of 4 and 7 S components were estimated to be 60, 000-70, 000 and 150, 000-160, 000, respectively.
Re-association of DEAE-dissociated hemocyanin in the presence of 0.5M NaCl or 0.01M CaCl2 was investigated by means of ultracentrifugation and electron microscopy. In contrast with Dolabella hemocyanin dissociated by EDTA (1), aggregation of fraction I by CaCl2 was random and incomplete. Fraction II compponents were scarcely re-associated by the salts.
Oxygen affinity of DEAE-dissociated hemocyanin was twice as large as that of native Dolabella hemocyanin, while n-value in Hill's equation showed only a slight decrease.
