Protein working with

Clearly, the results of osmotic pressure measurements on solutions of charged colloidal particles, such as proteins, will be invalid unless precautions are taken either to eliminate or to correct for this Donnan effect. Working at the isoelectric pH of the protein will eliminate the Donnan effect but will probably introduce new errors due to coagulation of the protein. Working with a moderately large salt concentration and a small protein concentration will make the... 

P. Gerber. Peptide mechanics a force field for peptides and proteins working with entire residues as the smallest units. B potymers j2 ivQi-lQ 7 (1992). 

Some forms of agarose are specifically designed to work with large (mol wt >500,000) molecules (27,28). The types of samples for which the agarose ief system are utilized are larger plasma proteins such as immunoglobulins, tissues, and tumors. 

After 1900, genetic research—but not research on nucleic acids—blossomed. Nucleic acids were difficult to work with, hard to purify, and, even though they were present in all cells, did not seem to be very interesting. Early analyses, later shown to be inconect, were interpreted to mean that nucleic acids were polymers consisting of repeats of some sequence of adenine (A), thymine (T), guanine (G), and cytosine (C) in a 1 1 1 1 ratio. Nucleic acids didn t seem to offer a rich enough alphabet from which to build a genetic dictionary. Most workers in the field believed proteins to be better-candidates. 

The analyst should be aware that generally, when working with large molecules (particularly proteins), column efficiencies may, under some circumstances, be as little as 10% of the expected value and this must be taken into account when choosing the column and the phase system. 

Molecular replacement is where the phases of a known structure are used to determine the structure of a protein that may be identical but crystallized in a different space group or may adopt essentially the same structure (e.g., a homologous protein). Essentially, the calculations find the rotation and translation of the molecule that work with the phases to produce an interpretable electron density map. 

Out of the work with HT-XPIPE it became clear to the consortium that there was a need to expand the automated molecular replacement protocol embodied in HT-XPIPE to handle scenarios in which either the target was a new project or ligand-binding caused a packing change in the protein that... 

Some work has been completed on reaction of proteins with nitrite followed by hydrolysis and analysis for amino acids It has been shown that 3-nitrotyrosine and 3,4-dihydroxyphenylalanine are formed from bovine serum albumin when nitrosation occurs under conditions similar to those found in the human stomach (36), Direct demonstration that nitrite reacts with protein has been made by using NaN02 with bovine serum albumin (pH 5.5, 20 C and 200 ppm nitrite). A 60% loss of the originally added nitrite was observed in one week and nearly half of the nitrite (labelled %) could be recovered from the protein. Similar work with myosin revealed that 10-20% of the incorporated label was present as 3-nitrotyro-sine (J7). 

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