Amino acid sequence of the N-terminus and selected tryptic peptides of the active subunit of human plasma carboxypeptidase N: comparison with other carboxypeptidases.
Article Details
- CitationCopy to clipboard
Skidgel RA, Bennett CD, Schilling JW, Tan FL, Weerasinghe DK, Erdos EG
Amino acid sequence of the N-terminus and selected tryptic peptides of the active subunit of human plasma carboxypeptidase N: comparison with other carboxypeptidases.
Biochem Biophys Res Commun. 1988 Aug 15;154(3):1323-9.
- PubMed ID
- 3408501 [ View in PubMed]
- Abstract
Human plasma carboxypeptidase N was purified to homogeneity and its active and inactive subunits were separated. By introducing a novel technique, both forms of the active subunit (Mr = 55,000 and Mr = 48,000) were isolated. N-terminal sequencing of the active subunit of human carboxypeptidase N revealed significant homology with the N-terminal sequence of bovine carboxypeptidase H (43% identity) and to a lesser extent with carboxypeptidase A (29% identity) or carboxypeptidase B (18% identity). The active subunit of carboxypeptidase N was hydrolyzed with trypsin and 4 of the tryptic peptides were isolated by HPLC and sequenced. The sequences of the four peptides were homologous (39-64% identity) with regions of carboxypeptidase H corresponding to the middle (residues 148-175) and C-terminal portion (residues 321-408). These regions had essentially no homology with carboxypeptidase A or B. These data indicate that carboxypeptidase H and the active subunit of carboxypeptidase N may have diverged from a common ancestral gene.