Abstract
| Original language | English |
|---|---|
| Pages (from-to) | 508-519 |
| Journal | Journal of Biotechnology |
| Volume | 127 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 2007 |
| MoE publication type | A1 Journal article-refereed |
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Keywords
- Silk sericin
- Chitosan
- Tyrosinase
- HP-SEC
- FT-IR
- DSC
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Tyrosinase-catalyzed grafting of sericin peptides onto chitosan and production of protein-polysaccharide bioconjugates. / Anghileri, Anna; Lantto, Raija; Kruus, Kristiina; Arosio, Cristina; Freddi, Giuliano (Corresponding Author).
In: Journal of Biotechnology, Vol. 127, No. 3, 2007, p. 508-519.Research output: Contribution to journal › Article › Scientific › peer-review
TY - JOUR
T1 - Tyrosinase-catalyzed grafting of sericin peptides onto chitosan and production of protein-polysaccharide bioconjugates
AU - Anghileri, Anna
AU - Lantto, Raija
AU - Kruus, Kristiina
AU - Arosio, Cristina
AU - Freddi, Giuliano
PY - 2007
Y1 - 2007
N2 - The capability of Agaricus bisporus tyrosinase to catalyze the oxidation of tyrosine residues of silk sericin was studied under homogeneous reaction conditions, by using sericin peptides purified from industrial wastewater as the substrate. Tyrosinase was able to oxidize about 57% of sericin-bound tyrosine residues. The reaction rate was higher than with silk fibroin, but lower than with other silk-derived model peptides, i.e. tryptic and chymotryptic soluble peptide fractions of silk fibroin, suggesting that the size and the molecular conformation of the substrate influenced the kinetics of the reaction. The concentration of tyrosine in oxidized sericin samples decreased gradually with increasing the enzyme-to-substrate ratio. The average molecular weight of sericin peptides significantly increased by oxidation, indicating that cross-linking occurred via self-condensation of o-quinones and/or coupling with the free amine groups of lysine and, probably, with sulfhydryl groups of cysteine. The high temperature shift of the main thermal transitions observed in the differential scanning calorimetry curves confirmed the formation of peptide species with higher molecular weight and higher thermal stability. Fourier transform-infrared spectra of oxidized sericin samples showed slight changes related to the loss of tyrosine and formation of oxidation products. Oxidized sericin peptides were able to undergo non-enzymatic coupling with chitosan. Infrared spectra provided clear evidence of the formation of sericin–chitosan bioconjugates under homogeneous reaction conditions. Spectral changes in the NH stretching region seem to support the formation of bioconjugates via the Michael addition mechanism.
AB - The capability of Agaricus bisporus tyrosinase to catalyze the oxidation of tyrosine residues of silk sericin was studied under homogeneous reaction conditions, by using sericin peptides purified from industrial wastewater as the substrate. Tyrosinase was able to oxidize about 57% of sericin-bound tyrosine residues. The reaction rate was higher than with silk fibroin, but lower than with other silk-derived model peptides, i.e. tryptic and chymotryptic soluble peptide fractions of silk fibroin, suggesting that the size and the molecular conformation of the substrate influenced the kinetics of the reaction. The concentration of tyrosine in oxidized sericin samples decreased gradually with increasing the enzyme-to-substrate ratio. The average molecular weight of sericin peptides significantly increased by oxidation, indicating that cross-linking occurred via self-condensation of o-quinones and/or coupling with the free amine groups of lysine and, probably, with sulfhydryl groups of cysteine. The high temperature shift of the main thermal transitions observed in the differential scanning calorimetry curves confirmed the formation of peptide species with higher molecular weight and higher thermal stability. Fourier transform-infrared spectra of oxidized sericin samples showed slight changes related to the loss of tyrosine and formation of oxidation products. Oxidized sericin peptides were able to undergo non-enzymatic coupling with chitosan. Infrared spectra provided clear evidence of the formation of sericin–chitosan bioconjugates under homogeneous reaction conditions. Spectral changes in the NH stretching region seem to support the formation of bioconjugates via the Michael addition mechanism.
KW - Silk sericin
KW - Chitosan
KW - Tyrosinase
KW - HP-SEC
KW - FT-IR
KW - DSC
U2 - 10.1016/j.jbiotec.2006.07.021
DO - 10.1016/j.jbiotec.2006.07.021
M3 - Article
VL - 127
SP - 508
EP - 519
JO - Journal of Biotechnology
JF - Journal of Biotechnology
SN - 0168-1656
IS - 3
ER -