Peptide cleavage

Chrysanthemic acid, structure of, 107 Chymotrypsin, peptide cleavage with, 1033... 

Proteases (proteinases, peptidases, or proteolytic enzymes) are enzymes that break peptide bonds between amino acids of proteins. The process is called peptide cleavage, a common mechanism of activation or inactivation of enzymes. They use a molecule of water for this, and are thus classified as hydrolases. 

Proteases are enzymes that break peptide bonds in proteins. As such they lend themselves to a variety of homogeneous assay techniques. Most employ labeling both ends of the substrate with a different tag, and looking for the appearance (disappearance) of the signal generated in the intact substrate (product). As an example, for a fluorescence quench assay, the N-terminal of a peptide is labeled with DNP and the C-terminal with MCA. As such, the peptide is fluorescently silent since the fluorescence from DNP is quenched by absorption by the MCA. Another very popular donor/acceptor pair is EDANS 5-[(2-aminoethyl)amino] naphthalene-1-sulfonic acid and DABCYL 4-(4-dimethylaminophenylazo)benzoic acid) (a sulfonyl derivative (DABSYL) [27], Upon peptide cleavage, the two products diffuse, and due to a lack of proximity, the fluorescence increases. 

Bark, S. J. and Hahn, K. M. (2000). Fluorescent indicators of peptide cleavage in the trafficking compartments of living cells Peptides site-specifically labeled with two dyes. Methods 20, 429-435. 

K Barlos, O Chatzi, D Gatos, G Stavropoulus. 2-Chlorotrityl chloride resin. Studies on anchoring of Fmoc-amino acids and peptide cleavage. Int J Pept Prot Res 37,513,... 

Extensive peptide cleavage only minor quenching... 

The first success in sequence-specific peptide cleavage by an antibody was claimed by Iverson (Iverson and Lemer, 1989). He used hapten [43] containing an inert Cora(trien) complexed to the secondary amino acid of a... 

Howe, C., and Wallace, T. (1990). Prediction of leader peptide cleavage sites for polypeptides of the thylakoid lumen. Nucl. Acids Res. 18, 3417-3417. 

Jain, R., Rusch, S., and Kendall, D. (1994). Signal peptide cleavage regions. Functional limits on length and topological implications./. Biol. Chem. 269, 16305-16310. 

J. B. A. Ross, K. W. Rousslang, C. DeHaen, V. R. Lavis, and D. A. Deranleau, [12-Homo-argininejglucagon Synthesis and observations on conformation, biological activity, and copper-mediated peptide cleavage, Biochim. Biophys. Acta 576, 372-384 (1979). 

A medicinal example is provided by klerval (Fig. 6.18). The aspartic acid residue in this tripeptide analogue is also a site of chemical instability. At pH 1, cleavage of the Asp-Xaa bond (Fig. 6.18, Reaction b) was second in importance after C-terminal deamidation (see Sect. 6.3.2.1), and cleavage of the Xaa-Asp bond (Fig. 6.18, Reaction c) was third. At pH 4, cleavage of the Asp-Xaa bond was the major reaction and was accompanied by the formation of the succinimide and the iso-aspartyl peptide cleavage of the Xaa-Asp bond was minor. At pH 7, the major products were the L-iso-Asp and D-iso-Asp peptides, together with minor amounts of the D-Asp peptide. 

Protein synthesis and folding Signal peptide cleavage Formation of disulfide bonds Oligomerization A/-Clycosylation folding... 

Aspartame is an alternative sweetener that is produced via a biocatalytic route. Aspartame is composed of two L-amino acids, which Why can t aspartame be made out of racemic amino acids How could one find an enzyme to couple the two amino acids (think of hydrolases, even though these normally cleave peptide bonds) What criteria should one have in mind when doing so How could one reverse the peptide cleavage reaction Would you use the purified enzyme to produce aspartame ... 

Vasopressin is administered by intravenous or intramuscular injection. The half-life of circulating vasopressin is approximately 15 minutes, with renal and hepatic metabolism via reduction of the disulfide bond and peptide cleavage. 

The best way to show you t>ow the overlap method of peptide sequencing works is by a specific example. In this example, we will illustrate the use of the two most commonly used enzymes for selective peptide cleavage. One is trypsin, a proteolytic enzyme of the pancreas (MW 24,000) that selectively catalyzes the hydrolysis of the peptide bonds of basic amino acids, lysine and... 

Know the meaning of amino acid sequence, Sanger s reagent, Edman degradation, selective peptide cleavage. 

Given information on selective peptide cleavage and the sequences of fragment peptides, deduce the sequence of the original polypeptide. 

MG Cordingley, PL Callahan, VV Sardana, VM Garsky, RJ Colonno. Substrate requirements of human rhinovirus 3C protease for peptide cleavage in vitro. J Biol Chem 265 9062-9065, 1990. 

The cysteine proteases can be divided into three classes the papain-like, the caspases (and related enzymes), and the picorna viral cysteine proteases. The proposed catalytic mechanism for cysteine protease peptide cleavage is related to the serine protease mechanism but with a cysteine thiol acting as the nucleophile that attacks the scissile peptide bond carbonyl. 

---