Sodium amino acid sequences

Rebif is produced via recombinant DNA technology in a CHO cell line. It displays an identical amino acid sequence to that of native human IFN-P-la and, like the native product, is glycosylated. After cell culture the interferon is purified using a series of chromatographic steps (affinity, ion-exchange, gel-filtration and reverse-phase liquid chromatography). It is formulated as a sterile solution in pre-filled syringes and contains mannitol, HSA, sodium acetate, acetic acid and sodium hydroxide as excipients. It is administered subcutaneously three times weekly. 

Neorecormon is one such product. Produced in an engineered CHO cell line constitutively expressing the EPO gene, the product displays an amino acid sequence identical to the native human molecule. An overview of its manufacturing process is presented in Figure 6.7. The final freeze-dried product contains urea, sodium chloride, polysorbate, phosphate buffer and several amino acids as excipients. It displays a shelf-life of 3 years when stored at 2-8 °C. A pre-filled syrine form of the product (in solution) is also available, which is assigned a 2 year shelf-life at 2-8 °C. 

These peptides produced the same taste. The interesting point was that Asp-Asp, took the largest amount of sodium ion, produced the weakest taste. The taste intensity of Asp-Asp was about 1/4 of that of Asp-Glu which produced the strongest taste. These results showed that sodium ion intake capacity and taste intensity depend on amino acid sequence of acidic peptides. We have to carefully think about these facts when we construct the taste of foods and carry out sodium ion diet. 

Since the Schiff base formation is reversible, it should be reduced by sodium borohydride for the fixation of the label. The rate of the reduction of the Schiff base becomes slow as the number of the phosphate groups of the label increases. However, except for adenylate kinase, the NP -PL bound to the proteins were easily fixed by borohydride reduction. After reductive fixation, labeled proteins are cleaved by appropriate methods. The labeled lysine is cleaved by neither trypsin nor lysyl endopeptidase. There are at least three ways to detect the labeled peptide during isolation 1) use of radioactive reagent, 2) use of radioactive sodium borohydride for reduction of the Schiff base, and 3) use of fluorescence derived from the pyridoxyl moiety of the reagent (excitation at 295 nm and emission at 390 nm at acidic pH). The labeled lysyl residue is not positively identified in the amino acid sequence analysis. However, the presence of the label in the peptide isolated can be confirmed by the presence of pyridoxyl lysine in the amino acid analysis. 

Rybalko, V.M., Oksas, A.E., Morozov V.A. (2005). Sodium and potassium metabolism under intoxication with organophos-phorus agents. Vestnik Rossiiskoi Medicinskoi Akademii [Bulletin of Russian Medical Academy] 1(4) 252. (In Russian) Sanger, F. (1963). Amino-acid sequences in the active centers of certain enzymes. Proc. Chem. Soc. 5 76-83. 

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