Aspartic acid, peptides

Souza, E.D., Ginsberg, M.H., Lam, S., and Plow, E.F. (1988) Chemical cross-linking of arginylglycyl-aspartic acid peptides to an adhesion receptor on platelets./. Biol. Chem. 263, 3943-3951. 

Liu et al. (2007) discovered that polyethylene glycol (PEG)ylated SWNTs are stable in vivo and demonstrate long blood circulation times and low uptake by the reticuloendothelial system. This group linked PEGylated SWNTs to an arginine-glycine-aspartic acid peptide, which was able to effectively target tumors in mice. 

RGD arginine-glycine-aspartic acid peptide sequence... 

Bone sialoprotein, osteopontin, and osteocalcin are synthesized and deposited as the mineralization process begins and mineral nodules form (Stein and Lian, 1993). Bone sialoprotein contains the cell-adhesive arginine-glycine-aspartic acid peptide sequence and may thus mediate osteoblast adhesion on the extracellular matrix (Gehron-Robey, 1989). Osteocalcin, a calcium-binding protein, interacts with hydroxyapatite and is thought to mediate coupling of bone resorption (by osteoclasts) and bone formation (by osteoblasts and/or osteocytes) (Stein and Lian, 1993). 

Acid proteases are inactivated by active-site specific reagents, diazoacetylnorleucine ethyl ester and other diazo compounds, and epoxy (p-nitrophenoxy)propane. Covalently labelled aspartic acid peptides have been isolated from pepsin, chymosin (= rennin), and penicillopepsin. The peptides labelled with the diazo compounds have similar sequences and differ from the epoxy (p-nitrophenoxy)pro-pane labelled peptides. These results indicate two aspartic acids at the active site and suggest homology between the enzymes. The latter is confirmed by a comparison of the sequence data. Studies of the action of porcine pepsin and penicillopepsin on some dipeptides with free N-terminal groups show transpeptidation involving a covalent acyl intermediate. It is proposed that there are differences in the mechanism of action of pepsin which are determined by the nature of the substrate. 

RGD is the one-letter amino acid code abbreviation for arginine-glycine-aspartic acid. Peptide sequences containing a RGD motif are used as specific ligands to mediate cell adhesion. 

Asparagine residues in peptides and proteins undergo deamidation via cyclic imide formation followed by subsequent hydrolysis to form the corresponding aspartic and Ao-aspartic acid peptides. This mechanism occurs primarily under neutral-to-basic pH conditions. Deamidation of an asparagine residue to the corresponding aspartic acid residue may also occur via a mechanism that does not involve cyclic imide formation, as shown in Scheme 80. Glutamine residues also undergo deamidation, but at much slower rates. 

Deamidation of ACTH under acidic pH conditions is considered to be direct deamidation to the aspartic acid peptide since the Ao-aspartic acid peptide was not observed as a... 

Peptides and proteins having an aspartic acid residue undergo hydrolysis, isomerization, and racemization via cyclic imide formation. As shown in Scheme 80, L-aspartic acid peptide can isomerize to L-iso -aspartic acid peptide via its L-cyclic imide. The L-cyclic imide intermediate is capable of undergoing racemization to the D-cyclic imide and thus forms the D-aspartic acid peptide and the D-Ao-aspartic acid peptide on hydrolysis. 

It is clear from the results that the structure of wool is extremely complex. Almost all of the monoamino acids occur linked to both sides of glutamic and cysteic acids. The small number of aspartic acid peptides identified is probably due to the lower content of aspartic acid in wool so that the peptide spots would probably be faint and would not show on the chromatograms. 

FITC-labeled HPMA copol3rmer conjugates containing aldendronate and aspartic acid peptide have recently been synthesized (276). Their ability to target bone was examined in vitro using a hydroxyapatite model and in vivo in mice. 

Polymer additives can improve manufacturing processes and product quality, as they aid the formation of a continuous coating phase without any detrimental effect to the polymer. Biomedical applications of acrylic terpolymer with arginylglycylaspartic acid, i.e., a tripeptide composed of L-arginine, glycine and L-aspartic acid peptides, have been studied by Fussell and Cooper [39]. Chauhan and co-workers have investigated the biological activities of synthesised terpolymers based on p-hydroxybenzaldehyde... 

Cooper, M. L., Hansbrough, J. F., and Polarek, J. W. (1996). The effect of an arginine-glycine-aspartic acid peptide and hyaluronate synthetic matrix on epitfaelialization of meshed skin graft interstices, /. Burn. Care Rehabil. 17(2) 108-116. 

Hansbrough, J. F., Herndon, D. N., Heimbach, D. M., Solem, L. D., Gamelli, R. L., and Tompkins, R. G. (1995), Accelerated healing and reduced need for grafting in pediatric patients with bums treated with arginine-glycine-aspartic acid peptide matrix RGD Study Group, /. Burn Care Rehabil. 16(4) 377-387. 

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