PRIMARY STRUCTURE OF GOLFINGIA GOULDII HEMERYTHRIN . INTERPEPTIDE OVERLAPS AND SEQUENCES FROM CHYMOTRYPTIC PEPTIDES

Peptides from chymotryptic digests of hemerythrin were isolated by a rapid method which employed preliminary fractionation by gel filtration and further purification by ion-exchange chromatography where necessary, and by paper electrophoresis and chromatography. They were then characterized chemically. Twenty-five major peptides were obtained. Twelve of these provided overlaps between the tryptic peptides obtained in previous work (Groskopf, W. R., Holleman, J. W., Margoliash, E., and Klotz, I. M. (1966a), Biochemistry 5, 3783); the others could be assigned to individual tryptic peptides. Some uncertainties in sequence were resolved by detailed sequence analysis of certain of the chymotryptic peptides. In this way the 113 residues of the hemerythrin monomer were arranged in sequence within four fragments: an N-terminal one containing 29 residues, a C-terminal one containing 46 residues, and two inner fragments of 4 and 34 residues, respectively. Amino acid substitutions at two points in the chain in samples of hemerythrin from pooled blood were noted. © 1968, American Chemical Society. All rights reserved.