Iridine amino acid sequence

F. The Amino-Acid Sequences of One Component of Salmine and Three Components of Iridine... 

The amino-acid sequences of some components obtained homogeneously from salmine and iridine have recently been established with the help of a new enzymic degradation method in addition to the usual procedures (Ando and Watanabe, 1969 Watanabe and Ando, to be published). 

Chart VIII-9. The amino acid sequences of salmine AI, iridine I (a) and (b), and iridine II with demonstration of peptides obtained by enzymic hydrolyses. The symbols used are A, Arg T, tryptic peptide Tm, thermolysin peptide NP, Neutral Protease peptide NP-7-NP, redigested Neutral Protease peptide from NP-No. 7 Tm-6-NP, Neutral Protease peptide from Tm-No. 6 (from Ando and Watanabe, 1969)... 

The chemical structures of these peptides were established in the usual way by quantitative amino-acid analysis and sequence analysis by a combination of chemical and enzymic methods, including dinitrophenylation, dansylation, Edman degradation, hydrazinolysis and digestion with leucine aminopeptidase and carboxypeptidases A and B. The Neutral Protease peptides of the salmine and iridine components or derivatives thus identified are listed in Table VIII-6 with their recovery values. Differences in the amino-acid sequences and amounts of the peptides obtained from iridine I aroused the suspicion that two molecular species (a and b) were present in the iridine I component. This result, as already described, was supported by observations on the thermolysin peptides of iridine I. 

To summarize for one component of salmine (S-AI) and three components of iridine (I-Ia, I-Ib and I-II) complete amino-acid sequences were deduced as shown in Chart VIII-9, from the information obtained from three sets of peptides resulting from digestion with trypsin, thermolysin, and Neutral Protease, as well as from the N- and C-terminal sequences. 

Ando, T., Watanabe, S. A new method for fractionation of protamines and the amino acid sequences of one component of salmine and three components of iridine. Int. J. Protein Res. 1, 221—224 (1969). 

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