Protein phases applications

The isomorphous replacement method requires attachment of heavy atoms to protein molecules in the crystal. In this method, atoms of high atomic number are attached to the protein, and the coordinates of these heavy atoms in the unit cell are determined. The X-ray diffraction pattern of both the native protein and its heavy atom derivative(s) are determined. Application of the so-called Patterson function determines the heavy atom coordinates. Following the refinement of heavy atom parameters, the calculation of protein phase angles proceeds. In the final step the electron density of the protein is calculated. 

Substrates for the creation of protein microarrays were initially selected from those used for DNA arrays, for example, PLL glass slides. At first, these substrates proved to be sufficient for antibody microarray studies. However, not all proteins will behave well or similarly on a particular substrate material. New solid phases applicable for protein microarrays need to be found. 

Hearn, M.T., M.I. AgnUar, T. Nguyen, and M. Fridman, High-performance liquid chromatography of amino acids, peptides and proteins. LXXXTV. Application of derivative spectroscopy to the study of column residency effects in the reversed-phase and size-exclusion liquid chromatographic separation of proteins. J Chromatogr, 1988. 435(2) 271-84. 

Tauc, R, Cochet, S., Algiman, E., CaUebaut, 1., Cartron, J.-R, Brochon, J.C., and Bertrand, O. 1998. Ion-exchange chromatography of proteins Modulation of selectivity by addition of organic solvents to mobile phase Application to single-step purification of a protei-... 

Utility of reverse phase protein arrays applications to signalling pathways and human body arrays. Brief Fund. Genomic Proteomic 1, 305-315. 

Analyses of phase boundaries reveal evidence for polymer saturation in the presence of excess protein. Phase boundaries also facilitate comparisions of the behavior of various proteins. The failure of net surface charge density as a universal parameter for protein-polyelectrolyte interaction is believed to be related to the existence of "charge patches" on the protein surface. The determination of a more realistic protein charge parameter possesses great importance, since the ionic interactions of proteins are exploited in a variety of applications, including protein purification via ion exchange liquid chromatography. 

Protein phases are expensive and delicate in handling and their performances (as plate numbers) and loadabilities are low. For many applications this is largely outweighed by their excellent enantioselectivity. 

Deak J, Richard L, Pereira M, Chui H-L and Miller R J D 1994 Picosecond phase grating spectroscopy applications to bioenergetics and protein dynamics Meth. Enzymol. 232 322-60... 

Applications of ultrafast spectroscopy to chemical dynamics, especially in the condensed phase and in proteins. 

A number of examples have been studied in recent years, including liquid sulfur [1-3,8] and selenium [4], poly(o -methylstyrene) [5-7], polymer-like micelles [9,11], and protein filaments [12]. Besides their importance for applications, EP pose a number of basic questions concerning phase transformations, conformational and relaxational properties, dynamics, etc. which distinguish them from conventional dead polymers in which the reaction of polymerization has been terminated. EP motivate intensive research activity in this field at present. 

An important difference between Protein-Pak columns and other size exclusion columns is the silica backbone of the Protein-Pak columns. Because the silica structure is unaffected by the solvent, these columns do not swell or shrink as a function of the solvent. This is a general advantage compared to other size exclusion columns. However, silica-based columns can only be used up to pH 8, which limits their applicability. Also, surface silanols are accessible for interaction with the analytes, but this phenomenon has been minimized by proper derivatization techniques. Generally, a small amount of salt in the mobile phase eliminates interaction with silanols. 

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