The Asn-Gly-Arg (NGR) motif and its deamidation product isoAsp-Gly-Arg (isoDGR) have recently attracted considerable attention as tumor-targeting ligands. Because an NGR-containing peptide and the corresponding isoDGR-containing peptide target different receptors, the spontaneous NGR deamidation can be used in dual targeting strategies. It is well known that the Asn deamidation proceeds via a s...

Chemical stability is a major concern in the development of protein therapeutics due to its impact on both efficacy and safety. Protein "hotspots" are amino acid residues that are subject to various chemical modifications, including deamidation, isomerization, glycosylation, oxidation etc. A more accurate prediction method for potential hotspot residues would allow their elimination or reductio...

Asparagine residues in proteins undergo spontaneous deamidation, a post-translational modification that may act as a molecular clock for the regulation of protein function and turnover. Asparagine deamidation is modulated by protein local sequence, secondary structure and hydrogen bonding. We present NGOME, an algorithm able to predict non-enzymatic deamidation of internal asparagine residues i...

BACKGROUND & AIMS Gluten (GLU)-specific T-cell responses in HLA-DQ2 positive adult celiac disease (CD) patients are directed to an immunodominant alpha-gliadin (GLIA) peptide that requires deamidation for T-cell recognition. The aim of the current study was to determine which GLU peptide(s) are involved early in disease. METHODS We have characterized the GLU-specific T-cell response in HLA-DQ...

With this system, no deamidation of glutamine occurred in the absence of a-keto acid, and, with all keto acids tested except two (pyruvate and a-ketobutyrate), transamination was absent or extremely slow when glutamate was substituted for glutamine. Experiments with W-labeled glutamine indicated that the ammonia evolved during this reaction was derived from t.he amide group of glutamine. Althou...

Wheat gluten protein (WGP) is a fine-quality plant-based resource. However, as its unparalleled reticulation structure, the processing properties of WGP are extremely poor, limiting application. To overcome these drawbacks, purpose this work was to embellish wheat by three relatively novel and mainstream chemical modifications. The results showed pH-shifting treatment altered apparent morpholog...

A method for the quantitative estimation of instability with respect to deamidation of the asparaginyl (Asn) residues in proteins is described. The procedure involves the observation of several simple aspects of the three-dimensional environment of each Asn residue in the protein and a calculation that includes these observations, the primary amino acid residue sequence, and the previously repo...

The authors are with the U.S. Dept. of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 E. Mermaid Lane, Wyndmoor, PA 19038. Direct inquiries to Dr. C.V. Santos. ABSTRACT Casein precipitated by carbon dioxide (CO2-casein), and commercial sodium and calcium caseinates (1% w/v in water) were thermally deamidated at pH 8 for up to 96h at 85, 100, and 1158C. CO2-cas...

Microheterogeneity of rabbit muscle aldolase is caused by deamidation in vivo of an asparagine residue near the C-terminus of each subunit. Isotopic labeling of a peptide containing the asparagine residue at various time intervals before isolation of aldolase permits estimation of the half-time for the deamidation as about 8 days, which is about the time estimated for the half-life of the enzym...

Wheat gliadin was deamidated by using a cation-exchange resin in the presence or absence of added cysteine, with the change in digestibility being measured. The allergenicity of the gliadin was evaluated by using sera from patients RAST-positive to wheat. Gliadin-specific IgE was measured after the gliadin had been orally administered to rats. The addition of cysteine before the treatment with ...