High-yield cleavage of tryptophanyl peptide bonds by o-iodosobenzoic acid

Abstract

A new procedure to cleave tryptophanyl peptide bonds in high yield is reported. The method involves treatment of the S-alkylated protein with o-iodosobenzoic acid. The procedure is highly selective for tryptophan and does not modify tyrosine or histidine, but may convert methionine to its sulfoxide derivative. The yields in the cleavage are 70--100%. Tryptophanyl bonds to alanine, glycine, serine, threonine, glutamine, arginine, and S-(pyridylethyl)cysteine are split in nearly quantitative yield, while those preceding isoleucine or valine are split in approximately 70% yield in the proteins examined in this work. The chemical mechanism for tryptophanyl bond cleavage has not been defined, but it is likely that oxidation of the indole ring occurs during the reaction with o-iodosobenzoic acid. Some problems with the quality of commercial preparations of the reagent are discussed.

The complete amino acid sequence of human muscle glyceraldehyde 3‐phosphate dehydrogenase

“…These results were confirmed by a new procedure of protein fragmentation [8,9] which was used to split the 3 tryptophanyl peptide bonds. We have succeeded in obtaining 4 homogeneous peptides OX-3 (2-84) 01-2 (8%193) 01-l (194-310)and 01-4 (311-332) in one step purification procedure.…”

Purification and amino acid sequence determination of an endo-1,3-β-glucanase from barley

“…Cleavage with o-iodosobenzoic acid in the presence af tyramine was done in 80% acetic acid containing 4 M guanidinium chloride for 5 hrs in the dark at room temperature (18). The resulting peptides were desalted on a BioGel P-6 (0.9x60 cm) column equilibrated with 30% acetic acid.…”

Chemical modifications of proteins: history and applications

“…Reagents and procedures have been developed to decrease immunogenicity (9,20), to increase and decrease susceptibility to proteolysis (22)(23), to increase UV or visible absorbancy (14), to introduce fluorescent labels (25,16), spin labels (27), radiolabels , various metal ions (22), magnetic microspheres (22,23), and electron-dense substituents (24), to increase the content of certain low-abundance nonradioactive isotopes (25), and to attach several different types of carbohydrate moieties (26)(27)(28)(29), biotin (30), and a number of other biospecific recognition groups (i.e., avidin, streptavidin, antibodies, protein A, protein G, lectins, and others (32)). Procedures also have been developed to effect the cleavage of peptide chains (32,33); to modify enzyme specificity (34); to modify the terminal hydroxyls of galactosyl residues in glycoproteins (35); to introduce intramo- 1 The Ohio State University. 1 University of California.…”