Detergents, peptides

Fatty Held—Peptide Condensates. These proteia detergents are reaction products of fatty acid chlorides and hydrolyzed proteias. They are used ia shampoos because of their mildness on skin, hair, and to eyes when used alone or ia combination with alkyl surfactants (8). 

Surfactants, Detergents, and Enzymes Bioactive peptides, lytic enzymes, anionic surfactants Biodispersants and Biodetergents... 

Swiderek, K. M. Alpert, A. J. Heckendorf, A. Nugent, K. Patterson, S. D. Structural analysis of proteins and peptides in the presence of detergents Tricks of the trade. ABRF News 1997. 

It is emphasized that revealing the dynamics as well as the structure (or conformation) based on several types of spin-relaxation times is undoubtedly a unique and indispensable means, only available from NMR techniques at ambient temperature of physiological significance. Usually, the structure data themselves are available also from X-ray diffraction studies in a more refined manner. Indeed, better structural data can be obtained at lower temperature by preventing the unnecessary molecular fluctuations, which are major subjects in this chapter, since structural data can be seriously deteriorated for domains where dynamics are predominant even in the 2D or 3D crystalline state or proteoliposome at ambient temperature. It should be also taken into account that the solubilization of membrane proteins in detergents is an alternative means to study structure in solution NMR. However, it is not always able faithfully to mimick the biomembrane environment, because the interface structure is not always the same between the bilayer and detergent system. This typically occurs in the case of PLC-81(1-140) described in Section 4.2.4 and other types of peptide systems. 

The effectiveness of proteolytic, amylolytic, and lipolytic detergent enzymes is based on enzymatic hydrolysis of peptide, glucosidic, or ester linkages. The mainstay of the market has been the protease types. 

Solid-phase peptide synthesis offers a fast and convenient route for many peptides when isotope-enriched compounds are not required. Classical synthesis additionally permits the use of non-natural amino acids and allows site-specific isotope labeling. Although Fmoc protected 15N-labeled amino adds are commercially available, the cost of such synthesis is usually prohibitive, and the peptides from chemical synthesis require perdeuterated detergents and unfortunately exclude investigation of internal dynamics through measurement of 15N relaxation. 

Detergents commonly used to form micelles that are amenable to high-resolution NMR are summarized in Tab. 5.2, and the chemical structures of the most commonly used detergents are presented in Fig. 5.2. Unfortunately, only a few of those needed for use with nonisotopically enriched peptides are commercially available in deuterated form. Most frequently, the zwitterionic DPC or the negatively charged SDS have been used as membrane mimetics. Mixtures of DPC doped with small amounts of SDS may be used to modulate the charge distribution on the micelle surface. It should be emphasized here... 

One positive side-effect of working with detergent solutions is that peptide samples tend to be stable over longer periods at higher temperatures. 

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