Arginine protein digestion

Ion suppression is not limited to just HPLC-MS or ESI interfaces. For MALDI analysis, arginine-containing peptides have been reported to dominate the peptide pattern for protein digests,the extent of which depends on the matrix used. The presence of ionic detergents, such as Triton X-100 and Tween 20, has also been shown to cause signal suppression in MALDI experiments, which can be countered by modifications to the matrix. ... 

Foettinger, A. Leitner, A. Linder, W. Derivatisation of arginine residues with malon-dialdehyde for the analysis of peptides and protein digests by LC-ESI-MS/MS. J. Mass Spectrom. 2006, 41, 623-632. 

On the average, tryptic peptides from protein digests contain only about 10 amino acids. This size peptide can be sequenced easily by the solid-phase method, provided they do not contain aspartic acid residues. Sequencing of arginine and tryptophan peptides was not attempted in the... 

Protein. Dietary protein increases the rate of calcium absorption from the small intestine. The probable explanation of this phenomenon is that the amino acids, especially lysine and arginine, liberated in the course of protein digestion, form soluble calcium salts which are easily absorbed. But any advantage from increased absorption will likely be more than counterbalanced by the increas urinary loss of calcium on high-protein diets. 

Trypsin (Section 27 10) A digestive enzyme that catalyzes the hydrolysis of proteins Trypsin selectively catalyzes the cleavage of the peptide bond between the carboxyl group of lysine or arginine and some other amino acid... 

The proteolytic digestion of j6-lactoglobulin was carried out with trypsin which, as indicated in Table 5.4 above, is expected to cleave the polypeptide backbone at the carboxy-terminus side of lysine (K) and arginine (R). On this basis, and from the known sequence of the protein, nineteen peptide fragments would be expected, as shown in Table 5.7. Only 13 components were detected after HPLC separation and, of these, ten were chosen for further study, as shown in Table 5.8. 

A protein identification study might proceed in the following manner. Pirst, the protein is analyzed by mass spectrometry to determine its molecular mass to within 0.01%. Second, the protein is digested with an enzyme, commonly trypsin. The enzyme trypsin cleaves polypeptide chains at points following lysine and arginine residues. Using this proteolytic enzyme ensures that each... 

Two-dimensional electrophoresis [86] is a well established technique for the separation of intact proteins. In the first dimension the proteins are separated based on their isolectric point while the second dimension separates them based on their size. The presence on the gel of the proteins is revealed by Coomassie blue or silver staining. Under favorable conditions several thousand spots can be differentiated. The gel is digitized and computer-assisted analysis of the protein spot is performed. The spots of interest are excised either manually or automatically and then digested with trypsin. Trypsin cleaves proteins at the C-terminal side of lysine and arginine. In general one spot represents one protein and the peptides are analyzed by MALDI-TOF to obtain a peptide mass fingerprint. A peptide mass fingerprint involves the determination of the masses of all pep-... 

Trypsin is the most frequently used serine protease. Generally, porcine or bovine pancrease is used as the source of pure trypsin. Trypsin usually digests proteins at their lysine and arginine residues. The superiority of trypsin is that it displays good activity both in solution and in-gel digestion protocols. 

Under a variety of conditions, plasmid DNA undergoes a dramatic compaction in the presence of condensing agents such as multivalent cations and cationic polymers. Naked DNA coils, typically with a hydrodynamic size of hundreds of nanometers, after condensation it may become only tens of nanometer in size. Contrary to proteins which show a unique tertiary structure, DNA coils do not condense into unique compact structure. Cationic polymers execute their gene carrier function by their condensation effect on gene materials and, furthermore, their protection effect on DNA from nuclease digestion. Currently, the most widely used cationic polymers in research include linear or branched PEI (poly (ethyleneimine) (161-165), polypeptides such as PLL (poly-L-lysine) (166-169), PLA (poly-L-arginine) (170). 

Yeast protein is easily digested (87%) and provides amino acids essential to human nutrition. Most commercial yeasts show the following pattern of amino acids, among others, as percent of protein 8.2% lysine 5.5% valine 7.9% leucine 2.5% methionine 4.5% phenylalanine 1.2% tryptophan 1.6% cystine 4% histidine 5% tyrosine and 5% arginine. The usual therapeutic dose of dried yeast is 40 grams/day, which supplies significant daily needs of thiamine, riboflavin, niacin, pyridoxine, and general protein. 

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