Polymer and Materials Science
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Analogs of natural proteins have application in basic research, in medicine, and increasingly, in industry. Of the many methods developed for the fabrication of modified proteins, semisynthesis has so far been the most productive [R. E. Offord (1983) Proc. Eur. Peptide Symp., 17 31-42]. The technique of fragment-condensation semisynthesis takes as its basic raw material the native protein; fragments derived from it are manipulated by sequential degradation and resynthesis before recombination. While gene manipulation may overtake protein manipulation in general usefulness, certain types of analogs will remain accessible only by semisynthesis. Fragment condensation semisynthesis, as described above, has been used in preparing cytochrome c analogs [C. J. A. Wallace (1979) Proc. Am. Peptide Symp. 6, 609-612]. To overcome the difficulty of replacing amino acids far from convenient cleavage sites, a number of variants of the method have also been used. These include fragment-specific chemical modification [C. J. A. Wallace & K. Rose (1983) Biochem. J. 215, 651-658] and solid-phase synthesis of small [P. J. Boon, G. I. Tesser, H. H. K. Brinkhof & R. J. F. Nivard (1981) Proc. Eur. Peptide Symp. 16, 127-130] or large fragments [L. E. Barstow, R. S. Young, E. Yakali, J. J. Sharp, J. C. O'Brien, P. W. Berman & H. A. Harbury (1977) Proc. Natl. Acad. Sci. USA 74, 4148-4250]. The latter study gave low final recoveries, so we have prepared large peptides (38-42 residues) by classical solution methods. We have examined both their use in the reformation of the complete protein, and the physical and biochemical properties of the product analogs compared with those of the native proteins.
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