Silk proteins, sericin and fibroin in silkworm, Bombyx mori Linn., A review


Silkworm Physiology Laboratory, Central Sericultural Research and Training Institute Mysore, 570008, Karnataka, India.


The domesticated silkworm, Bombyx mori Linn., a lepidopteran molecular model and an important economic insect that are emerging as an ideal molecular genetic resource for solving a broad range of biological problems. The silkworm, B. mori produces massive amount of silk proteins during the final stage of larval development. These proteins are stored in the middle silk gland and they are discharged through the anterior duct and spinneret, at the end of the fifth instar. Two kinds of silk proteins have been distinguished as major components of silk cocoons, the first being fibroin, a fibrous protein composed of heavy (H) chain, Light (L) chain and glycoprotein linked by disulfide bonds and the second being sericin a natural macromolecular protein, serving as an adhesive to unite fibroin for making silk cocoons of silkworm, B. mori. Recently, silkworm is being used as biofactory for the production of useful protein using the silk gland, which has promoted the technological development in sericulture. With the above background silkworm can be classified as a value added biomaterial for medical application, application of silk protein fibroin and sericin as a biomaterial and other seri-byproducts. The present paper overviews some important studies carried out on sericin and fibroin of silkworm, Bombyx mori

Ahn, J.S., Choi, H.K., Lee, K.H., Nahm, J.H. and Cho, S. (2001) Novel mucoadhesive polymer prepared by template polymerrization of acrylic acid in the presence of silk sericin. J. Appl. Polym. Sci. 80, 274–280.
Akai, H., Imai, T. and Tsubouchi, K. (1987) Fine structural changes of liquid silk in the silkgland during the spinning stage of Bombyx mori larvae. J. seric. Sci. Jpn. 56, 131-137.
Akai, H.T., Nagashima, T., Inoue, S., Kobayashi, I. and Tarmura, T. (2005) Functional recovery of transgenic silk gland. 20th congress of the international sericultural commission, Bangalore, India, December 15- 18, p. 119.
Annamaria, S., Maria, R., Tullia, M., Silvio, S. and Orio, C. (1998) The microbial degradation of silk: a laboratory investigation. Int. Biodeterior. Biodegrad. 42, 203– 211.
Asakura, T., Yamare, T., Nakazawa, Y., Kamada, T. and Ando, K. (2001) Structure of Bombyx mori silk fibroin before spinning in solid state studied with wide angle Xray scattering and 13 cross polarization/ magic angle spinning NMR. Biopolymers. 58, 521-525.
Aslani, M.A. and Eral, M. (1994) Investigation of uranium recovery from dilute aqueous solutions using silk fibroin. Biol. Trace Elem. Res. 43, 737-743.
Bose, P.C., Majumdar, S.K. and Sengupta, K. (1989) Role of the amino acids in 74 Proteins, sericin and fibroin in silkworm silkworm, Bombyx mori L. nutrition and their occurrence in haemolymph, silk gland and silk cocoons –A review. Indian J. Seric. 28, 17-31.
Chavancy, G. (2005) Silkworm for non-textile industries. Souveni, 20th congress of the international sericultural commission, Bangalore, India 15-18th December 2005. pp. 1-6.
Chevillard, M., Couble, P. and Prudhomme, J.C. (1986a) Complete nucleotide sequence of the gene encoding the Bombyx mori silk protein P25 and predicted amino acid sequence of the protein. Nucleic Acids Res. 14, 6341-6342.
Chevillard, M., Deleage, G. and Couble, P. (1986b) Amino acid sequence and putative conformational characteristic of the P25 silk protein of Bombyx mori. Sericologia. 26, 435-449.
Chisti, Y. (1998) Strategies in downstream processing; in Bioseparation and bioprocesssing: a handbook. G. Subramanian (ed). New York: Wiley-VCH. pp. 3-30.
Demura, M., Asakura, T., Kuroo, T., (1989) Immobilization of biocatalysts with Bombyx mori silk fibroin by several kinds of physical treatment and application to glucose sensors. Biosensors, 4, 361-372.
Feiying, S., Boxiong, Z., Chenfu, L., Bo, H., Jianke, L.I., Jianying, L.I., Jifeng, J., Kefeng, X.U., Uanjie, Y.Y., Jianshe, L., Haisheng, X.U., Songkun, S.U. and Guohua, Y. (2005) Analysis of protein variety of the middle silk gland cells of the 5th instar larvae of silkworm Bombyx mori L., 20th congress of the international sericultural commission, Bangalore, India, December 15-18, p. 119.
Gamo, T. and Soto, S. (1985) Ultra structural study of the posterior silk gland in the Nd, Nd-s and Ns-s mutants with a defect of fibroin synthesis. J. seric. Sci. Jpn. 54, 412- 419.
Gregory, H.A., Diaz, F., Caroline, J., Tora, C., Rebecca, L.H., Jingsong, C., Helen, L., John, R. and David, L.K. (2003) Silk based biomaterials. Biomaterials. 24, 401-416.
Gotoh, K., Izumi, H., Kanamoto, T., Tamada, Y., Nakashima, H. (2000) Sulfated fibroin, a novel sulfated peptide derived from silk, inhibits human immunodeficiency virus replication in vitro. Biosci Biotechnol Related Articles, Books Biochem. 64, 1664-1670.
Gulrajani, M.L. (1988) Degumming of silk; in Silk dyeing printing and finishing, M.L. Gulrajani (ed), Department of Textile Technology Indian Institute of Technology, New Delhi. pp. 63-95.
Gulrajani M.L. (2005) Sericin: A Bio-molecule of value. Souveni 20th congress of the international sericultural commission, Bangalore, India 15-18th December 2005. pp. 21-29.
Hatakeyama, H. (1996) Biodegradable sericin-containing polyurethane and its production. Japan Patent 08-012738A.
Hu, K. (2006) Biocompatible Fibroin Blended Films with Recombinant Human-like Collagen for Hepatic Tissue Engineering. Journal of Bioactive and Compatible Polymers. 21, 23-37.
Iizuka, E. (1969) Silk sericin of Bombyx mori L. Biochem. Biophys. Acta. 181, 477-479.
Inoue, S., Tanaka, K., Arisaka, F., Kimura, S., Ohtomo, K. and Mizuno, S. (2000) Silk fibroin of Bombyx mori is secreted, assembling a high molecular mass elementary unit consisting of H-chain, Lchain and P25, with a 6:6:1 molar ratio. J. Biol. Chem. 275, 40517-40528.
Inoue, S., Kanda, T., Imamura, M., Quan, G.X., Kojma, K., Tanaka, H., Tomita,M., Hino, R., Yoshizato, K., Mizuno, S. and Tamura, T. (2005) A fibroin secretion deficient silkworm mutant, Nd-sD, provides an efficient system for producing recombinant proteins. Insect Biochem. Mol. Biol. 35, 51-90.
Inouye, K., Kurokawa, M., Nishikawa, S. and Tsukada, M. (1998) Use of Bombyx mori silk fibroin as a substratum for cultivation of animal cells. J.Biochem. Biophys. Meth. 18, 159-164.
Ishikawa, H. and Hirabayashi, K. (1968) Compilation of studies of silk reeling and silk. Seishi – Kinu Kenkya – Happyo Shuroku, 18, 56-59. Ishikawa, H., Nagura, M. and Tsuchiya, Y. (1987) Fine structure and physical properties of blend film compose of silk sericin and poly (vinyl alcohol). Sen’i Gakkaishi , 43, 283–270.
Jain, Y.E., Jianying, L.I., Jine, C. and Boxing, Z. (2005) Analysis of 2D-page patterns of protein from posterior silk gland of different breeds silkworm Bombyx mori L. on the 4th day in 5th instar. 20th congress of Mondal et al., 75 the international sericultural commission, Bangalore, India 15-18th December. p. 120.
Kato, N., Sato, S., Yamanaka, A., Yamadam, H., Fuwam, N. and Nomura, M. (1998) Silk protein, sericin, inhibits lipid peroxidation and tyrosinase activity. Biosci. Biotechnol. Biochem. 62, 145–147.
Kenji, O., Somashekar, R., Noguchi, K. and Syuji, I. (2001) Refined molecular and crystal structure of silk I based on Ala-Gly and (Ala-Gly)2 Ser-Gly peptide sequence. Biopolymers. 59, 310-319.
Komatsu, K. (1975) Studies on dissolution behaviors and structural characteristic of silk Sericin. Bull. Sericult. Exp. Sta. 26, 135- 256.
Komatsu, K., 1980, Recent advances in sericin research. J. Sericult. Sci. Japan. 69, 457-465. Komatsu, K. (1982) Silk III. Sericin physical structure. Sericologia. 22, 14-23.
Konishi, T. (2000) Structure of fibroin – α in Structure of silk yarn. Hojo, N. (ed) Oxford and IBH publication Co. Pvt. Ltd., New Delhi. pp. 267-277.
Kurioka, A. and Yamazaki, M. (2002) Purification and idetification of flavonoids from the yellow green cocoon shell (Sasamayu) of the silkworm, Bombyx mori. Biosci. Biotechnol. Biochem. 66, 1396-1399.
Li, X. (1996) Usages of sericin in durable material. China patent.1116227A. Matta, A., Migliaresi, C., Faccioni, F., Torricelli, P., Fini, M. and Giardino, R. (2004) fibroin hydrogels for biomedical applications, preparation, characterization and in vitro cell culture studies. J. Biomater. Sci. Polym. 15, 851-864.
Murase, M. (1994) Method for solubilizing and molding cocoon silk, artificial organ made of cocoon silk, and medical element made of cocoon silk. Japan Patent 06- 166850A.
Minoura, N., Aiba, S., Gotoh, Y., Tsukada, M. and Imai, T. (1995) Attachment and growth of cultured fibroblast cells on silk protein matrices. J. Biomed. Mat. 29, 1215– 1221.
Miyairi, S. and Sugiura, M. (1978) Properties of b-glucosidase immobilized in sericin membrane. J. Fermen. Tech. 56, 303–308.
Mizoguchi, K., Iwatsubo, T. and Aisaka, N. (1991) Separating membrane made of cross-linked thin film of sericin and production thereof. Japan Patent. 03- 284337A.
Mori, K., Tanaka, K., Kikuch, Y., Waga, M., Waga, S. and Mizuno, S. (1995) Production of a chimeric fibroin light-chain polypeptide in a fibroin secretion- deficient naked pupa mutant of the silkworm Bombyx mori. J.Mol. Bio. 251, 217-228.
Nakajima, Y. (1994) Liquid crystal element. Japan Patent 06-018892.
Padamwar, M.N., Pawar, A.P., Daithankar, A.V. and Mahadik, K.R. (2005) Silk sericin as a moisturizer an in vivo study. J. Cosmet. Dermat. 4, 250-257.
Phillips, D.M., Drummy L.F., Naik, R.R., Delong, H.C., Fox, D.M., Trulove, P.C. and Mantz, R.A. (2005) Silk fibers from an ionic liquid solution. J. Mater. Chem. 15, 4206.
Robson, R.M. (1985) Silk composition, structure and properties; in Hand book of fibre Science and Technology, Vol. 4, Lewin, M and E.M pearce (eds.), Mercel. Dekker Inc, New York. pp. 649-700.
Rui, H.G. (1998) Quality of Cocoon Filament; in Silk reeling. H. G Rui (ed), Oxford & IBH Publication Co. Pvt. Ltd., New Delhi, pp. 58-69.
Sadov, F., Korchagin, M. and Matetsky, A. (1987) Chemical technology of fibrous materials. Mir Publication, Moscow, pp. 306-307.
Shimizu, M. (2000) Structural basis of silk fibre; in Structure of silk yarn” vol I biological and physical aspects. N. Hojo (ed.), Oxford & IBH Publication Co. Pvt. Ltd., New Delhi, pp. 7-17.
Shimura, K., Kikuchi, A., Katagata, Y. and Ohtomok, K. (1982) The occurrence of smallest component protein in the cocoon of Bombyx mori. J. Seric. Sci. Jpn. 51, 20-26.
Tamada, Y. (1997) Anticoagulant and its production. Japan Patent 09-227402A.
Tanaka, K., Kajiyama, N., Isohikura, K., Waga, S., Kukuchi, A., Ohtomo, K., Takagi, T. and Mizuno, S. (1999) Determination of the site of disulfide linkage between heavy and light chain of silk fibroin produced by Bombyx mori. Biochem. Biophys. Acta. 1432, 92-103.
Tanaka, K. amd Mizuno, S. (2001) Homologues of fibroin L-chain and P25 of Bombyx mori are present in Dendrolimus spectabilis and Papilio xuthus but not detectable in Antheraea yamamai. Insect 76 Proteins, sericin and fibroin in silkworm Biochem. Mol Biol. 31, 665-677.
Tokutake, S. (1980) Isolation of the smallest component of silk protein. Biochemistry Biochem. J. 187, 413-417. Tsubouchi, K. (1999a) Wound covering material. US patent 5951506.
Tsubouchi, K. (1999b) Occlusive dressing consisting essentially of silk fibroin and silk sericin and its production. Japan Patent 11-070160A.
Tsukada, M. (1983) Structure of silk sericins removed from wild silk by boiling in water. J. Sericult. Sci. Japan. 52, 296-299.
Tsukada, M., Hayasaka, S., Inoue, K., Nishikawa, S. and Yamamoto, S. (1999) Cell culture bed substrate for proliferation of animal cell and its preparation. Japan Patent 11-243948A.
Wu, C.Y., Tian, B.Z., Zhu, D., Yan, X.M., Chen, W and Xu, G.Y. (1996) Properties and application of wound protective membrane made from fibroin. In International silk congress, Suzou Institute of silk technology, Suzou, China, 25-28th October, pp 79-87.
Yamada, M. (1978) Amino acid composition of the sericin extracted from cocoon of the mulberry wild silkworm, Bombyx mori and its species specificity. J. Sericult. Sci. Japan. 47, 108-112.
Yamada, H., Fuwa, N. and Nomura, M. (1993) Synthetic fiber having improved hygroscopicity. Japan patent 05-339878A.
Yamada, H. and Fuwa, N. (1994) Protein containing high molecular material and its application. Japan patent 06-080741A.
Yamaguchi, K., Kikuchi, Y., Takagi, T., Kikuchi, A., Oyama, F., Shimura, K. and Mizuno, S. (1989) Primary structure of the silk fibroin light chain determined by cDNA sequencing and peptide analysis. J. Mol. Bio. 210, 127-139.
Yamamoto, T., Miyajima, T., Mase, K. and Iizuka, T. (2002) Breeding of silkworm race ‘Sericin hope’ secreting silk protein in which sericin is contained high concen tration. Annual report of National institute of Agrobiological Science, Japan. pp. 99-100.
Yoshimura, T., Shimizu, Y., Kurotani, W., Yamaoka, R. and Hayashiya, K. (1989) Application of fibroin membrane to immobilizing coenzed insect cell culture for use as vaccine. Agri and Biol. Chem. 52, 3201-3202.
Yoshii, F., Kume, N., Makuuchi, K. and Sato, F. (2000) Hydrogel composition containing silk protein. Japan Patent 06-017373A.
Zhaorigetu, S.N., Sasakim M., Watanbe, H. and Kato, N. (2003) Silk protein, sericin, suppresses DMBA-TPA induced mouse skin tumorigenesis by reducing oxidative stress, inflammatory responses and endogenous tumor promoter TNF-alpha. Oncol Rep. 10, 537-543.
Zhou, C.Z., Confalonieri, F., Medina, N., Zivanovic, Y., Esnault, C., Jacquet, T., Janin J., Duguet, M., Perasso, R. and Liz, G. (2000) Fine organization of Bombyx mori fibroin heavy chain gene. Nucl. Acids Res. 28, 2413-2419.