Isolation of a Disulfide Bridge Containing Fragment of the Variable Part of Pig Immunoglobulin λ‐Chains

The pig immunoglobulin λ‐chains with intact disulfide bonds were subjected to hydrolysis by trypsin. Gel filtration of the hydrolyzate and icon‐exchange chromatography on SE‐Sephadex yielded a fragment containing 70—71 amino acid residues. It is composed of two sections which can be separated after reduction of a disulfide bond. The amino acid composition of resulting peptides shows that they contain variable sequences. One of the peptides has a blocked N‐terminal amino group. All data indicate that the isolated fragment originates in the variable part of the chain and that one of its sections includes the N‐terminus of the chain.