AMINO ACID COMPOSITION OF RIBONUCLEOPROTEIN OF SILKGLAND*

Abstract

From silkglands of Bombyx mori, L (Japanese 112 x Chinese 112) on the 5th day of the 5th instar, the purified ribonucleoprotein was isolated by the Griffins method. This protein contained 147 [mu]g and 28.5 [mu]g P/mg (N/P ratio=5.2), showed a band at 260 mu and was electrophoretically homogeneous. The amino acid composition of the protein moiety (73.2%) of this ribonucleoprotein was analyzed quantitatively by chemical and paper-chromatographical methods: Glycine 3.4, alanine 6.8, serine 13.5, tyrosine 4.2, valine 7.8, aspartic acid 13.4, glutamic acid 13.5, phenylalanine 3.6, threonine 2.7, leucine + isoleucine 10.0, proline 1.8, arginine 9.7% by weight. N-Terminal amino acids were identified as glycine, alanine and serine. Amino acid contents of silkprotein were determined also.