[Blue blood: structure and evolution of hemocyanin].

Hemocyanins are the oxygen-transporting proteins in arthropods and molluscs, the oxygen is bound by two copper atoms. Spectroscopic studies on the active site show similarities to the active site of a further group of copper-containing proteins, the tyrosinases. Arthropodan and molluscan hemocyanins form high-molecular aggregates which are markedly different in size and quaternary structure.

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.

Complete amino-acid sequence of a functional unit from a molluscan hemocyanin (Helix pomatia).

From the beta c-hemocyanin (beta c-Hc) of the vineyard snail, Helix pomatia, the functional unit d (Mr approximately equal to 50,000-55,000) was isolated by limited proteolysis and gel chromatography. A small quantity of functional unit d was obtained intact, but the major part in the form of two peptides (Mr approximately equal to 43,000 and 10,000, respectively) connected by a disulfide bridge. After reduction and carboxymethylation, these were separated from each other and cleaved by conventional methods.

The structure of arthropod hemocyanins.

Hemocyanins are large multi-subunit copper proteins that transport oxygen in many arthropods and molluscs. Comparison of the amino acid sequence data for seven different subunits of arthropod hemocyanins from crustaceans and chelicerates shows many highly conserved residues and extensive regions of near identity. This correspondence can be matched closely with the three domain structure established by x-ray crystallography for spiny lobster hemocyanin.

Carbonate dehydratase (carbonic anhydrase) in a spider. Association with the hemolymph lipoprotein.

Carbonate dehydratase was detected dissolved in the hemolymph of the tarantula, Eurypelma californicum. The enzyme was purified 31-fold by gel filtration, anion-exchange chromatography, a second gel filtration, and finally, preparative polyacrylamide gel electrophoresis. Zinc content increased during purification to up to 2.