Abstract
1. A solution of Bombyx mori silk fibroin was digested with chymotrypsin. Amino acid analyses of the chymotryptic precipitate showed in addition to the main constituents Gly, Ala, Ser and Tyr, very small amounts of Lys, His, Arg, Asp, Thr, Glu, Pro, Cys, Val, Met, Ile, Leu, Phe and Trp. 2. A stable solution of the chymotryptic precipitate in 6m-urea was obtained by dialysing a solution in 50% (w/v) lithium thiocyanate against 6m-urea. 3. The dinitrophenylated chymotryptic precipitate in 6m-urea was fractionated by gel filtration and by ion-exchange chromatography. On Dowex 1 (X2), a main fraction Id and three further fractions with different amino acid compositions and molecular weights were obtained. 4. Specific rearrangement and fission of the bonds involving the serine nitrogen atoms of fraction Id and fractionation of the resulting mixture by gel filtration yielded five fractions. Two of these fractions had the compositions DNP-Ser-(Gly6,Ala4,Ser) and DNP-Ser-(Gly4,Ala2 or Ala3,Ser) and are presumably double repeating units according to the proposed formula of Lucas, Shaw & Smith (1957), namely [Ser-Gly-(Ala-Gly)n]2, for n values of 2 and 1 respectively.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- DESNUELLE P., BONJOUR G. Nouvelles recherches sur l'hydrolyse préférentielle des liaisons sérine et thréonine dans les protéines. Biochim Biophys Acta. 1951 Sep;7(3):451–459. doi: 10.1016/0006-3002(51)90048-0. [DOI] [PubMed] [Google Scholar]
- ELLIOTT D. F. A search for specific chemical methods for fission of peptide bonds. I. The N-acyl to O-acyl transformation in the degradation of silk fibroin. Biochem J. 1952 Feb;50(4):542–550. doi: 10.1042/bj0500542. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LUCAS F., SHAW J. T., SMITH S. G. The amino acid sequence in a fraction of the fibroin of Bombyx mori. Biochem J. 1957 Jul;66(3):468–479. doi: 10.1042/bj0660468. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MIDDLEBROOK W. R. The chain weight of wool keratin. Biochim Biophys Acta. 1951 Nov;7(4):547–562. doi: 10.1016/0006-3002(51)90068-6. [DOI] [PubMed] [Google Scholar]