As a peptide

I don t know of any published results concerning 7-glutamyl peptides with one more peptide linkage at the amino group of the glutamic moiety. However, there is strong support that those types of compounds may also be easily hydrolyzed, although there is no possibility here to form any 

The other product of GSH-autohydrolysis, cysteinylglycine, undergoes cyclization when heated or on standing at room temperature. The dike-topiperazine is formed. This compound, i.e. the disulfide, may be easily obtained in the crystalline state. 

When GSH is oxidized in the presence of other thiols, mixed disulfides are formed e.g., during the process of autohydrolysis, if air is not excluded, formation of G—S—S—CHa—CH(NH2)—CO-NH—CH —CO2H takes place (38). With pantetheine also a mixed disulfide results (39). The high content of glutamic acid in crude preparations of coenzyme A is probably due to the existence of a mixed disulfide of CoA and GSH. 

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Caution During a sininlation, solvent temperature may increase wh ile th e so In te cools. This is particii larly true of sm all solven t molecules, such as water, that can acquire high translational and rotational energies. In contrast, a macromolecule, such as a peptide, retains most of its kinetic energy in vibrational modes. This problem rem ains un solved, an d this n ote of cau tion is provided to advise you to give special care to simulations using solvent. 

Proteins form in a sequence of condensation reactions in which the amine end of one amino acid combines with the carboxyl end of another, eliminating a water molecule to create an amide linkage. The amide group that connects two amino acids is called a peptide linkage, and the resulting molecule is known as a peptide. When two amino acids are linked, the product is a dipeptide. A dipeptide formed from alanine and glycine is shown in Figure 13-33. 

The addition of PEG to the gels was critical because the PEG chains participate in the macromolecular complexes, function as a peptide stabilizer and enhance the mucoadhesive characteristics of the gels. In this work, strong dose-dependent hypoglycemic effects were observed in healthy and diabetic rats following oral administration of these gels. 

It should also be noted that new sample probes can generate additions to the sample information queries asked of the user at the beginning of the "probe session." Thus, protein probes required the addition of queries regarding molecular weight, isoelectric point and whether biological activity is to be preserved in the chromatographic step. These questions are triggered only if the user specifies the sample as a peptide or protein in answer to the initial sample questions. Also, once the sample is specified as a protein, the question as to the pKa or pKb of the... 

Biological. Four Pseudomonas sp., including Pseudomonas putida (ATCC culture 29607) isolated from soil, degraded chloropicrin by sequential reductive dechlorination. The proposed degradative pathway is chloropicrin -> nitrodichloromethane nitrochloromethane nitromethane + small amounts of carbon dioxide. In addition, a highly water soluble substance tentatively identified as a peptide was produced by a nonenzymatic mechanism (Castro et al., 1983). 

In biochemistry, the amide linkage is traditionally referred to as a peptide bond. Whether the resultant polymer is classified as a peptide or a protein is not clearly defined generally, a chain length of more than 40 residues confers protein status, whereas the term polypeptide can be used to cover all chain lengths. 

TVpes of preparations (B). As a peptide, insulin is unsuitable for oral administration (destruction by gastrointestinal proteases) and thus needs to be given parenterally. Usually, insulin preparations are injected subcutaneously. The duration of action depends on the rate of absorption from the injection site. 

Caldtonin (p. 264) inhibits osteoclast activity, hence bone resorption. As a peptide it needs to be given by injection (or, alternatively, as a nasal spray). Salmonid is more potent than human calcitonin because of its slower elimination. 

Substmcture search of this backbone (smiles O = C(N(C)C1C)CN(C)C1=0) reveals several hundreds commercially available compounds, which likely have been synthesized by the above synthetic route [1]. This backbone can also be considered as a peptide mimetic by using a-amino acid derived isocyanide and amine components and will be of value for biological studies and for the discovery of hydrolysis resistant and biologically active peptide fragments (Fig. 6). 

Metabolism/Excretion - As a peptide, enfuvirtide is expected to undergo catabolism to its constituent amino acids, with subsequent recycling of the amino acids in the body pool. 

Many biological molecules, such as proteins, are large and have complex structures. Proteins are composed of a sequence of units, called amino acids, which are joined by a strong covalent bond known as a peptide bond. But proteins also fold up into a certain shape, which is vital to their function—a protein that loses its shape cannot fulfill its function as an enzyme or a transporter. The sequence of amino acids determines the shape 20 different amino acids are found in proteins, and each one has slightly different chemical and physical properties. For example, some amino acids are hydrophilic, readily interacting... 

We have already discussed the co-occurrence of small amine and peptide neurotransmitters their release is normally Ca + dependent, and they operate through signal transmission. They are also capable of regulating each other s release and even the synthesis, clustering, and affinity of receptors. Neuroendocrine cells are capable of producing more than one peptide, and thus an amine-peptide as well as a peptide-peptide combination is possible. It is known, for instance, that the vagus nerve contains substance P, vasointestinal peptide, enkephalin, cholecystokinin, and somatostatin— peptides with a hybrid combination of neural and hormonal communication properties. 

The condensation reaction between two amino acid molecules, usually in the form of active esters, produces a dipeptide molecule (equation 16). The resulting amide bond (—CONH—) is often referred to as a peptide bond. This condensation reaction can be repeated to give a polypeptide chain (18). In naming the sequence of amino acid residues in the chain the customary habit of starting from the N-terminal (free amino) end will be adopted. Synthetic polypeptides made from a single amino acid type, i.e. R1 = R2 = R3 = = R" in (18), are known as homopolypeptides. Cyclic peptide molecules are also known and can occur naturally. 

Peptides are a very heterogeneous group of compounds that share the common characteristic of being made up of chains of amino acids joined by an amide bond, also known as a peptide bond. The large number of different amino acids that exists in nature and the large variations in the number of amino acids in a given peptide mean that peptides can be highly diverse. 

The synthesis of a 158,400-membered encoded peptidomimetic library (96 x 50 x 33) is given in Scheme 2, using /3-Phe(4-NH2) as a trifunctional scaffold for the testing compound and Phe(4-NH2) as a peptide backbone... 

Conventional systems do not offer sufficient flexibility in controlling drug-release rate and sustaining the release over time periods extending from days to months. Therefore specific modified release vaginal delivery systems are continuously under development and are based on mucoadhesive systems. Penetration enhancement may represent a necessary feature for certain delivery systems, particularly when the absorption regards a macromolecule (such as a peptide or a protein). 

Polymer chemistry developed a nomenclature (language) different from the classical organic chemistry. The group "-NHCO-" in polymer chemistry is known as nylon, whereas in biochemistry it is known as a peptide, and in pure organic chemistry as an amide group. The urethane group "-NHCOO-" is called a carbamate in organic chemistry. 

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