A method for preparing β-hCG COOH peptide-carrier conjugates of predictable composition

doi:10.1016/0161-5890(80)90145-5

Molecular Immunology

Volume 17, Issue 6, June 1980, Pages 749-756

https://doi.org/10.1016/0161-5890(80)90145-5 Get rights and content

Abstract

A method for coupling peptides related to the beta subunit of human chorionic gonadotropin (hCG) to macromolecular carriers that permits covalent conjugation in a predictable fashion was developed. Peptides representing hCG beta subunit residues 109–145 and 111–145 were coupled to tetanus toxoid, flagellin, synthetic polypeptides and Ficoll. Carrier compounds containing amino groups but devoid of sulfhydryl groups were reacted with 6-maleimido caproic acyi N-hydroxy succinimide ester (MCS) under conditions that result in the bifunctional reagent attached to carrier amino groups with the stable maleimido group free. Subsequently, peptides containing sulfhydryl groups were reacted with the reagent modified carrier whereby the peptides coupled to the carrier via the reaction between sulfhydryl groups on peptide and the maleimido group on carriers. Peptides devoid of sulfhydryl groups were thiolated using homocysteine thiolactone. The efficiency of coupling was confirmed by amino acid analysis and SDS polyacrylamide electrophoresis. Results indicated that the coupling of peptides to carriers could be regulated by the number of moles of MCS reacted with carrier to yield free maleimido groups. Sulfhydryl group reaction with maleimido groups was stoichiometric. Conjugates prepared by this method were used to immunize rabbits and significant levels of antibodies to the hCG peptides have been attained.

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A method for preparing β-hCG COOH peptide-carrier conjugates of predictable composition

Abstract

J. biol. Chem.

J. Immun. Meth.

The labelling of proteins to high specific radioactivities by conjugation to a 125I-containing acylating agent

Biochem. J.

Thymus-independent antigens: the preparation of covalent, hapten-Ficoll conjugates

J. Immun.

Preparation and some properties of maleimido acids and maleoyl derivatives of peptides

Helv. Chim. Acta

The labelling of proteins to high specific radioactivities by conjugation to a ¹²⁵I-containing acylating agent