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The Arrangement of Amino Acids in Proteins

1952; Academic Press; Linguagem: Inglês

10.1016/s0065-3233(08)60017-0

1557-8941

Frederick Sanger,

Protein purification and stability

This chapter focuses on the accuracy of the peptide theory and on the possible existence of non- peptide bonds in proteins. Partition chromatography in the form of paper chromatography is a method that is identified as breakdown products of proteins where more peptides are used. This technique had been identified by the classical methods of organic chemistry. Three types of polypeptide chains are possible, open, cyclic and branched. There are two types of terminal residues, those with a free amino group and those with a free carboxyl group. The Dinitrophenyl (DNP) method is used for the separation and identification of peptides containing lysine. Elution can be effected with acid ethanol and the peptides subsequently fractionated on suitable partition chromatograms. The theoretical possibility exists that synthetic reactions may occur during the partial hydrolysis of proteins. Acid hydrolysis is the most used method of degrading proteins, and it is almost universally employed when amino acids are to be isolated or estimated, since it leads to complete hydrolysis with a minimum of destruction. Paper chromatography is preferred for the final fractionation of a simplified peptide mixture because of the good resolutions obtained, the ease and rapidity of technique, and the possibility of using the two-dimensional method. The chief disadvantage is that only a very small amount of each peptide can be obtained from a chromatogram, though it is usually possible to obtain sufficient material to determine the structure of di- and tri-peptides.