Quaternary and subunit structure of Calliphora arylphorin as deduced from electron microscopy, electrophoresis, and sequence similarities with arthropod hemocyanin.

Arylphorin was purified from larvae of the blowfly Calliphora vicina and studied in its oligomeric form and after dissociation at pH 9.6 into native subunits. In accordance with earlier literature, it was electrophoretically shown to be a 500 kDa hexamer (1 x 6) consisting of 78 kDa polypeptides (= subunits).

Allosteric oxygen-binding properties of reassembled tarantula (Eurypelma californicum) hemocyanin with incorporated apo- or met-subunits.

4x6-meric hemocyanin of the tarantula Eurypelma californicum was dissociated into subunits; one type of subunit was removed by immunoaffinity chromatography and replaced by its apo- or met-form. The mixture was reassembled and the reconstituted 4x6-mers were isolated. This was performed for subunits a, bc, d, e, f and g, respectively.

Tarantula (Eurypelma californicum) venom, a multicomponent system.

The venom of the tarantula Eurypelma californicum was analysed biochemically, the components were isolated and characterized. The pH value of the crude venom is 5.3 +/- 0.

Hemocyanins in spiders. XXII. Range of allosteric interaction in a four-hexamer hemocyanin. Co-operativity and Bohr effect in dissociation intermediates.

The range of allosteric interaction in the 24-meric hemocyanin from the tarantula Eurypelma californicum was studied by measuring the oxygen-binding properties of defined oligomeric fragments. Dissociation intermediates comprising 19, 12, 7 or 6 subunits were obtained by incubation of native hemocyanin with 10 mM-cysteine at pH 4.4, with 40 mM-dithiothreitol at pH 7 or 8, by short-term alkaline (pH 9.