Cyanogen bromide, cleavage

Fig. 24.8 Release of somatostatin from a hybrid protein by cyanogen bromide cleavage. Somatostatin can be purified free of cyanogen bromide and fragments of /J-galactosidase.

Location of the Modified Residues. In order to determine the location and number of amino acid residues reacted with ozone, the ozonized samples were allowed to undergo cyanogen bromide cleavage and trypsin digestions. 

Cytochrome c(l-65) and -(66-104), derived by cyanogen bromide cleavage, form a stable complex in which the 65-66 peptide bond spontaneously slowly re-forms to give a protein with full biological activity.1124 ... 

Regnouf, E Kassab, R. Fattoum, A. Primary structure of lobster-muscle arginine kinase. Isolation and characterization of the fragments produced by cyanogen-bromide cleavage. Eur. J. Biochem., 44, 67-79 (1974)... 

Spencer, E. M. 1974. Amino acid sequence of the alanyl peptide from cyanogen bromide cleavage of bovine plasma albumin. Arch. Biochem. Biophys. 165, 80-89. 

Cyanogen bromide cleavage of the polypeptide subunit should yield 4 peptides if the subunit contains 3 methionines (Table III). Cleavage products were isolated by gel filtration through Sephadex G-75 columns and analyzed for purity with polyacrylamide gel electrophoresis in 8 M urea containing 0.1 M thioglycolate. Four peptide products were obtained (34). 

Another approach has been the preparation of fragments of cytochrome c, in which the heme group is bound to a portion of the protein, either by tryptic digestion or cyanogen bromide cleavage. 

Cyanogen bromide cleaves peptides at the carboxyl side of Met. There is only one Met in the structure (see the fifth trypsin fragment), and the cyanogen bromide cleavage gives a hexapeptide consisting of the first six amino acids of this fragment. The N-terminal amino acid must be Tyr. We now know the first ten and the last two amino acids of p-endorphin. 

Figure 5-3. Mechanism of cyanogen bromide cleavage. Cyanogen bromide cleaves peptide chains at methionine residues. The reagent attacks the sulphur atom, and methylisothio-cyanate is cleaved from the resulting adduct,...

Fig. 19. Topography of the NBS cleavage of the six tyrosyl peptide links of native and

Figure 21 shows the previously published sequence of residues 11-18 of ribonuclease (Hirs, et al, I960). Previous studies (Redfield and Anfinsen, 1956 Anfinsen et al, 1956) have suggested that residue 11 is glutamic acid rather than serine. The results with cyanogen bromide cleavage discussed above are consistent with the latter assignment for position 11. Thus cleav-... 

Cyanogen bromide cleavage M is 10th position, C-terminal residues are (2S,L,W) Amino-terminal residues (G,K,S,Y), tryptic peptide, ends in K Amino-terminal sequence SYGK... 

Cyanogen bromide cleavage M is 10th position, C-terminal residues are (2S,L,W)... 

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