title: Immobilization of L-asparaginase on the microparticles of the natural silk sericin protein and its characters.
abstract: The natural silk sericin recovered from Bombyx mori silk waste by the degumming processing in the high-temperature and high-pressure is a macromolecular protein. Amino acid composition and molecular weight range of the sericin protein as a vector for enzyme immobilization were investigated. The silk sericin protein with different molecular mass from 50 to 200 kDa was poorly soluble microparticles with an average size of about 10 microm. Anti-leukemic enzyme L-asparaginase (L-ASNase) was covalently conjugated on the microparticles of the sericin protein. The immobilized L-ASNase on the natural support by cross-linking with glutaraldehyde maintained 62.5% of the original activity of the enzyme. The Km of sericin-conjugates was 8 times lower than that of native L-ASNase. The bioconjugation of L-ASNase widened the optimum reactive temperature range of the enzyme. The immobilized L-ASNase showed significantly higher stability when the temperature raised to 40-50 degrees C, it also showed preferable resistance to trypsin digestion as compared with native enzyme. The results are discussed regarding the possible explanations of sericin-induced enzyme stability, as well as the possible applications of immobilized L-ASNase research.
authors.affiliation: School of Agriculture Science and Technology, Soochow University, 1 Shizi St. Suzhou, Jiangsu 215006, China. yqzhang@public1.sz.js.cn
authors.forename: Yu-Qing
authors.initials: YQ
authors.lastname: Zhang
authors.forename: Mei-Lin
authors.initials: ML
authors.lastname: Tao
authors.forename: Wei-De
authors.initials: WD
authors.lastname: Shen
authors.forename: Yu-Zhen
authors.initials: YZ
authors.lastname: Zhou
authors.forename: Yue
authors.initials: Y
authors.lastname: Ding
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.forename: Wen-Lin
authors.initials: WL
authors.lastname: Zhou
mesh_terms: D000327:Adsorption; D000595:Amino Acid Sequence; D001215:Asparaginase / Q000737:chemistry*; D004789:Enzyme Activation; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry; D005960:Glucosides; D019476:Insect Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010316:Particle Size; D010456:Peptides, Cyclic / Q000737:chemistry*; D011485:Protein Binding; D047030:Sericins; D047011:Silk; D013696:Temperature; D014357:Trypsin / Q000737:chemistry
chemical_list: D004800:Enzymes, Immobilized; D005960:Glucosides; D019476:Insect Proteins; D010456:Peptides, Cyclic; D047030:Sericins; D047011:Silk; C020776:miserotoxin; D014357:Trypsin; D001215:Asparaginase