Studies on specific chemical fission of peptide links. Part I. The rearrangement of aspartyl and glutamyl peptides

Abstract

The esters of z-and P-aspartyl peptides (types I1 and X ; n = 1) have been converted by alkaline hydrolysis into mixtures of acidic aspartyl peptides of types (V) and (VI). In all cases studied, the former product preponderates.The rearrangement has been shown to occur by cyclisation to the related imides (IV) followed by hydrolysis. Esters of glutamyl peptides are rearranged in a similar way, but certain differences from the asparty1 analogues have been discovered. The possible application of this rearrangement in a scheme for the specific fission of a peptide chain a t the aspartic and glutamic residues is discussed.A PEPTIDE may be degraded for structural study by partial hydrolysis with acids or enzymes, or by stepwise removal of amino-acid residues from the ends of the chain. Advances in these fields were reviewed in 1952 by Khorana (Quart. Reviews, 6, 340) and several more recent contributions have been made (e.g.,

Blocked α‐amino groups in peptides due to diketopiperazine formation

“…Desamidative/3-aspartyl shifts are well known, especially with glycine, in natural [ 13] and synthetic peptides [14][15][16][17][18][19]. A substituent (amide or ester) on the/3-carboxyl group seems to be a prerequisite which is compatible with the sequence Asn-Gly in the original protein.…”

“…A substituent (amide or ester) on the/3-carboxyl group seems to be a prerequisite which is compatible with the sequence Asn-Gly in the original protein. Basic pH, which was used for the tryptic and chymotryptic digestions, facilitates the shift [14][15][16][17][18][19]. Significantly, it was not observed in the peptic digest carried out under acidic conditions.…”

Identification of 3-(O-β-Glucosyl)-2-Indolone-3-Acetylaspartic Acid as a New Indole-3-Acetic Acid Metabolite in Vicia Seedlings

“…The UV spectrum of the eluate from the fluorescent area showed a close resemblance to that of authentic QCA (Xmax 201 nm, e 26,400; 212, 29,600; 226, 28,100; 243, 9,400; 273, 6,000; 325, 6,000 in water) (Fig. 3).…”

Site‐Specific Cleavage—A Model System for the Identification of Lipid‐Modified Glutamate Residues in Proteins

“…[16] The chemical conversion of glutamic acid residues into 1-acylpyrrolidine-2-ones with thionyl chloride and pyridine has been proposed as a method for the specific cleavage of peptides at the N-terminal site of glutamate residues. [17][18][19][20] In this contribution, we report on the development of conditions that make use of this instability as an analytical tool for the mass spectrometric identification of ester-modified glutamic acid residues in peptides.…”