Purification and Characterization of Glue Proteins Secreted from the Colleterial Glands of the Silkworm, Bombyx mori

Abstract

The glue proteins from the collecterial glands of the adult female silkworm, Bombyx mori were purified and characterized by ion exchange chromatography on CM-Sephalose CL-6B, gel permeation chromatography on Sephacry-400 and electrophoresis. The purified glue proteins showed two major proteins, glue protein-1 (GP-1) and glue protein-2(GP-2). The molecular weights as determined by SDS-polyacrylamide gel electrophoresis on 7.5% gel were 240 and 190 KDa for GP-1 and GP-2, respectively, while by Sephacryl-400 gel permeation chromatography were 7,000 and 1,700 KDa, respectively. Furthermore, by using SDS-polyacrylamide gel electrophoresis on 15% gel small peptide (SP) was detected with molecular weight of 10 KDa and 26 KDa by Sephacryl1-400 column. Amino acid analysis of glue proteins were found to be in unusually high contents of glutamic acid and glycine. NH2-terminal sequences of glue proteins are also reported. Immunological analysis indicates GP-1 is the dominant of glue proteins.