Incomplete sequences

It was noted that the N-tcrminal end of /i. mori PBAN was identical to the incomplete sequence of melanization and reddish coloration hormone (MRCH) also isolated from B. mori. Subsequently, it was shown that B. mori PBAN is the same peptide as MRCH (Matsumoto et al 1990). This was the first indication that these peptides were involved in multiple functions. 

The sequence of the chicken GDH is remarkably similar to that of the bovine, with only 27 differences in the 500 amino acid residues which both enzymes possess in common, plus the three additional residues at the NHa-terminus of the chicken enzyme. The incomplete sequence of the rat liver enzyme (Fig. 4) also indicates great similarity to those of the other two vertebrates and as yet offers no clue as to why the rat enzyme does not polymerize. 

FIGURE 3 Comparison of the amino acid sequences of CPs from different species. The amino acid positions are numbered according to the chicken alpha (upper lane) and rat acidic (lower lane) sequences. Dots represent identical residues, horizontal bars indicate gaps introduced into the sequences for maximal alignment, and asterisks represent incomplete sequences. 

An unusual, although incomplete, sequence for achieving 7a-methoxylation of cephalosporins was executed by Saito and Hiraoka (1977c). The method comprises an intramolecular abstraction of active hydrogen by the anion of the C-7 ylide, concomitant with the elimination of triphenylphosphine (258) to form an imino intermediate. 

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