Lobster hemocyanin: properties of the minimum functional subunit and of aggregates.

Lobster hemocyanin dissociates into a functional subunit of 68,000 to 70,000 molecular weight when Ca(2+) ions are removed from an alkaline solution of low ionic strength. Succinylation results in a further dissociation into two nonfunctional subunits of approximately 34,000 to 35,000 molecular weight. Amino acid analysis and tryptic peptide patterns indicate that the functional subunit is composed of at least two polypeptide chains which are similar.