N-terminal modification of immunoglobulin polypeptide chains tagged with isothiocyanato chelates

Tariq M. Rana, Claude F. Meares

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Conjugates of monoclonal antibodies with drugs, toxins, radionuclides, and other agents are in widespread use in therapeutic trials and as clinical research tools. The characterization of these immunoconjugates generally does not include determining the individual sites at which such agents are attached. We have begun to explore the attachment of the bifunctional chelating agent isothiocyanatobenzyl-EDTA (CITC1) to the N-termini of the light chains of the Lym-1 monoclonal antibody. The similarity between this bifunctional chelating agent and Edman's reagent, phenyl isothiocyanate, led us to develop methods to distinguish between chelate-conjugated α-amino groups and ∈-amino groups by Edman degradation. Practically all the N-terminal Asp α-NH2 groups of Lym-1 can be modified at neutral pH, while attachment at lysine side chains predominates at pH 9. Comparison of the immunoreactivities of Lym-1-CITC conjugates with and without N-terminal conjugation shows that both are almost fully active. This implies that modification of light-chain N-termini has little or no effect on immunoreactivity, despite the fact that these residues lie near the antigen-binding sites.

Original languageEnglish (US)
Pages (from-to)357-362
Number of pages6
JournalBioconjugate Chemistry
Volume1
Issue number5
StatePublished - 1990

Fingerprint

Immunoglobulin Subunits
Polypeptides
Chelating Agents
Immunoconjugates
Light
Monoclonal antibodies
Therapeutic Uses
Viperidae
Chelation
Radioisotopes
Lysine
Binding Sites
Monoclonal Antibodies
Clinical Trials
Antigens
Degradation
Ethylenediaminetetraacetic acid
Binding sites
Research
Pharmaceutical Preparations

ASJC Scopus subject areas

  • Chemistry(all)
  • Organic Chemistry
  • Clinical Biochemistry
  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry

Cite this

N-terminal modification of immunoglobulin polypeptide chains tagged with isothiocyanato chelates. / Rana, Tariq M.; Meares, Claude F.

In: Bioconjugate Chemistry, Vol. 1, No. 5, 1990, p. 357-362.

Research output: Contribution to journalArticle

Rana, Tariq M. ; Meares, Claude F. / N-terminal modification of immunoglobulin polypeptide chains tagged with isothiocyanato chelates. In: Bioconjugate Chemistry. 1990 ; Vol. 1, No. 5. pp. 357-362.
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