Oligopeptide, sequencing

Tandem heterocycles are formed by posttranslational conversion of oligopeptide sequences consisted of serine, cysteine and threonine. A striking example of tandem heterocycles is telomestatin (Figure 7.2), a nanomolar telomerase inhibitor, which contains eight heterocycles. In its biosynthesis, five serines were converted to five oxazoles, two threonines to two methyloxazoles and one cysteine to one thiazoline [25]. 

The relationship between the structure of the oligopeptide sequences and the rate of enzymatically catalyzed release of a drug or drug model was studied in detail. Over 50 different oligopeptide sequences were introduced into HPMA copolymers and their degradability by different enzymes studied. First, model enzymes, chymotrypsin [235, 238,239, 243,244], trypsin [245], and papain... 

Considerable research has been devoted to assessment of the immunogenicity of HPMA copolymers.108-110 By themselves, HPMA copolymers do not elicit any immune response. When HPMA copolymers were modified with oligopeptides, only weak immunogenic responses were observed, and their intensity depended on the structure of the oligopeptide sequence and the host.111... 

On such modified surfaces, some of the attached proteins are recognized by cytoskeletally associated receptors in the cell membrane. So, in the end, the extracellular substrate is mechanically connected with the intracellular cytoskele-ton, which may secrete its own adhesion proteins. Integrins, as an important class of cell receptors [63], bind to small domains on their adhesion proteins, e.g., the oligopeptide sequence arginine-glycine-aspartic acid (RGD) that is common in fibronectin [64],... 

Several authors have compared imprinted polymers to biological receptors and even the term plastic antibodies has been coined to describe these remarkable materials. To a large extent, this comparison rests on a spectacular work of Mosbach and co-workers [24], who showed that theophylline- and diazepam-imprinted polymers displayed a specificity rather similar to that of polyclonal antibodies in binding studies with the template and its close structural analogues. However, it is the recognition of nucleotide or oligopeptide sequences which is... 

Rejmanova P, Kopecek J, Dimcan R, Lloyd JB. Stability in rat plasma and serum of lysosomally degradable oligopeptide sequences in N-(2-hydroxypropyl)methacrylamide copolymers. Biomaterials 1985 6 45-48. 

Oligopeptide sequences can be incorporated into N-(2-hydroxypropyl)methacryl-amide copolymers (for the different methods used see section 2) which serve as potential drug attachment/release sites and experiments have been carried out to investigate whether such sequences could be efficiently cleaved by lysosomal enzymes. 

Reaction between amines and the reactive HPMA copolymers forms the basis for attachment of oligopeptide sequences, targeting residues or therapeutic agents to the polymer precursor (Fig. 3). Reaction of aliphatic amines (tertiary butylamine and diisopropylamine) in dimethylsulphoxide at 25 C with reactive copolymers containing different side-chains has been used to characterize copolymer reactivity.It has been shown that copolymers of HPMA with p-nitrophenyl esters of a-(acylamino) acids react faster with amines than copolymers with p-nitrophenyl esters of g-(acyl-amino) acids or, e-(acylamino) acids.21... 

Rejmanova, P., B. Obereigner and J. Kopecek, Polymers contahiing enzy matically degradable bonds, 2. Polv[N-(2-hydroxvpropyl) methacrylamide] chains connected by oligopeptide sequences cleavable by chymotrypsin, Makromol. Clieni., 182 (1981) 1899-1915. 

Rejmanova, P., Kopecek, J., Duncan, R. and Lloyd, J.B. (1985) Stability in rat plasma and serum of Iv sosomally degradable oligopeptide sequences in At(2hydroxypropy4)methacrylamide copolymers,... 

An example in which aggregation posed a problem surfaced in the polymerization of monomers bearing the acid-rich oligopeptide sequence Glu-Cys-Asp-Val-Thr. Interest in generating polymers bearing this sequence was driven by its presence in fertilin p, a sperm protein that binds to the egg membrane [26-64]. Attempts to polymerize the peptide-substituted monomer... 

Many organisms, from invertebrates to humans, rely on conserved cationic amphipathic oligopeptide sequences to augment the immune system [105]. These antimicrobial peptides (AMPs) are secreted by immune cells to serve as first-line, broad-spectrum antibiotics [105]. Cationic AMPs associate with negatively charged bacterial membranes. 

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