Primary structure of hemocyanin subunit c from Panulirus interruptus

Abstract

The amino acid sequence of the hemocyanin subunit c from the spiny lobster, Panulirus interruptus, has been determined. The elucidation was mainly based on three digests, with CNBr, trypsin and endoproteinase Glu‐C, respectively. Additional evidence was obtained by sequencing of peptides from an endoproteinase Lys‐C digest. Subunit c is a polypeptide with 661 amino acid residues and with a carbohydrate group attached to residue 476 in the third domain. No heterogeneity was observed. The degree of identity with subunit a is 59%. Some differences with subunit a are an N‐terminal extension of six residues, a one‐residue C‐terminal extension, and a three‐residue deletion. Furthermore, carbohydrate attachment is in a different position, as are most half‐cystine residues. Limited trypsinolysis resulted in cleavage at the same site as in subunits a and b. Copyright © 1992, Wiley Blackwell. All rights reserved