Loosening of globular structure under alkaline pH affects accessibility of ß-lactoglobulin to tyrosinase-induced oxidation and subsequent cross-linking

Riitta Partanen (Corresponding Author), Mika Torkkeli, Maarit Hellman, Perttu Permi, Ritva Serimaa, Johanna Buchert, Maija-Liisa Mattinen

Research output: Contribution to journalArticleScientificpeer-review

16 Citations (Scopus)

Abstract

Globular proteins such as β-lactoglobulin (BLG) are poorly accessible to enzymes. We have studied susceptibility of BLG to oxidation by Trichoderma reesei (TrTyr) and Agaricus bisporus (AbTyr) tyrosinases and subsequent intermolecular cross-linking with respect to pH-induced structural changes. We evaluated pH-induced structural changes in BLG using circular dichroism, tryptophan fluorescence and small angle X-ray scattering (SAXS) measurements, where after these results were correlated with the analysis of cross-linking by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Oxygen consumption measurement and changes in radii of gyration determined by SAXS during the enzyme-induced oxidation at the respective reaction conditions were also followed. Intermolecular cross-linking of BLG by TrTyr was found at pH 9 but not at pH 7.5. AbTyr was unable to catalyze cross-linking at pH 7.5 or pH 9. Increased accessibility and cross-linking by TrTyr was addressed to loosening of the three dimensional structure of the protein, increased flexibility of the backbone as well as partial hydrolysis. In addition to basic research of the effect of protein folding on enzymatic cross-linking the research results have significance on the exploitation of TrTyr at alkaline conditions.
Original languageEnglish
Pages (from-to)131-138
JournalEnzyme and Microbial Technology
Volume49
Issue number2
DOIs
Publication statusPublished - 2011
MoE publication typeA1 Journal article-refereed

Fingerprint

Lactoglobulins
Monophenol Monooxygenase
X ray scattering
Enzymes
Proteins
Protein folding
Oxidation
Dichroism
Sodium dodecyl sulfate
Polyacrylates
Electrophoresis
Tryptophan
Sodium Dodecyl Sulfate
Hydrolysis
Gels
Fluorescence
Oxygen
X-Rays
Agaricus
Trichoderma

Keywords

  • ß-lactoglobulin
  • unfolding
  • hydrolysis
  • accessibility
  • tyrosinase
  • oxidation
  • cross-linking

Cite this

Partanen, Riitta ; Torkkeli, Mika ; Hellman, Maarit ; Permi, Perttu ; Serimaa, Ritva ; Buchert, Johanna ; Mattinen, Maija-Liisa. / Loosening of globular structure under alkaline pH affects accessibility of ß-lactoglobulin to tyrosinase-induced oxidation and subsequent cross-linking. In: Enzyme and Microbial Technology. 2011 ; Vol. 49, No. 2. pp. 131-138.
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abstract = "Globular proteins such as β-lactoglobulin (BLG) are poorly accessible to enzymes. We have studied susceptibility of BLG to oxidation by Trichoderma reesei (TrTyr) and Agaricus bisporus (AbTyr) tyrosinases and subsequent intermolecular cross-linking with respect to pH-induced structural changes. We evaluated pH-induced structural changes in BLG using circular dichroism, tryptophan fluorescence and small angle X-ray scattering (SAXS) measurements, where after these results were correlated with the analysis of cross-linking by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Oxygen consumption measurement and changes in radii of gyration determined by SAXS during the enzyme-induced oxidation at the respective reaction conditions were also followed. Intermolecular cross-linking of BLG by TrTyr was found at pH 9 but not at pH 7.5. AbTyr was unable to catalyze cross-linking at pH 7.5 or pH 9. Increased accessibility and cross-linking by TrTyr was addressed to loosening of the three dimensional structure of the protein, increased flexibility of the backbone as well as partial hydrolysis. In addition to basic research of the effect of protein folding on enzymatic cross-linking the research results have significance on the exploitation of TrTyr at alkaline conditions.",
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Loosening of globular structure under alkaline pH affects accessibility of ß-lactoglobulin to tyrosinase-induced oxidation and subsequent cross-linking. / Partanen, Riitta (Corresponding Author); Torkkeli, Mika; Hellman, Maarit; Permi, Perttu; Serimaa, Ritva; Buchert, Johanna; Mattinen, Maija-Liisa.

In: Enzyme and Microbial Technology, Vol. 49, No. 2, 2011, p. 131-138.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Loosening of globular structure under alkaline pH affects accessibility of ß-lactoglobulin to tyrosinase-induced oxidation and subsequent cross-linking

AU - Partanen, Riitta

AU - Torkkeli, Mika

AU - Hellman, Maarit

AU - Permi, Perttu

AU - Serimaa, Ritva

AU - Buchert, Johanna

AU - Mattinen, Maija-Liisa

PY - 2011

Y1 - 2011

N2 - Globular proteins such as β-lactoglobulin (BLG) are poorly accessible to enzymes. We have studied susceptibility of BLG to oxidation by Trichoderma reesei (TrTyr) and Agaricus bisporus (AbTyr) tyrosinases and subsequent intermolecular cross-linking with respect to pH-induced structural changes. We evaluated pH-induced structural changes in BLG using circular dichroism, tryptophan fluorescence and small angle X-ray scattering (SAXS) measurements, where after these results were correlated with the analysis of cross-linking by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Oxygen consumption measurement and changes in radii of gyration determined by SAXS during the enzyme-induced oxidation at the respective reaction conditions were also followed. Intermolecular cross-linking of BLG by TrTyr was found at pH 9 but not at pH 7.5. AbTyr was unable to catalyze cross-linking at pH 7.5 or pH 9. Increased accessibility and cross-linking by TrTyr was addressed to loosening of the three dimensional structure of the protein, increased flexibility of the backbone as well as partial hydrolysis. In addition to basic research of the effect of protein folding on enzymatic cross-linking the research results have significance on the exploitation of TrTyr at alkaline conditions.

AB - Globular proteins such as β-lactoglobulin (BLG) are poorly accessible to enzymes. We have studied susceptibility of BLG to oxidation by Trichoderma reesei (TrTyr) and Agaricus bisporus (AbTyr) tyrosinases and subsequent intermolecular cross-linking with respect to pH-induced structural changes. We evaluated pH-induced structural changes in BLG using circular dichroism, tryptophan fluorescence and small angle X-ray scattering (SAXS) measurements, where after these results were correlated with the analysis of cross-linking by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Oxygen consumption measurement and changes in radii of gyration determined by SAXS during the enzyme-induced oxidation at the respective reaction conditions were also followed. Intermolecular cross-linking of BLG by TrTyr was found at pH 9 but not at pH 7.5. AbTyr was unable to catalyze cross-linking at pH 7.5 or pH 9. Increased accessibility and cross-linking by TrTyr was addressed to loosening of the three dimensional structure of the protein, increased flexibility of the backbone as well as partial hydrolysis. In addition to basic research of the effect of protein folding on enzymatic cross-linking the research results have significance on the exploitation of TrTyr at alkaline conditions.

KW - ß-lactoglobulin

KW - unfolding

KW - hydrolysis

KW - accessibility

KW - tyrosinase

KW - oxidation

KW - cross-linking

U2 - 10.1016/j.enzmictec.2011.04.010

DO - 10.1016/j.enzmictec.2011.04.010

M3 - Article

VL - 49

SP - 131

EP - 138

JO - Enzyme and Microbial Technology

JF - Enzyme and Microbial Technology

SN - 0141-0229

IS - 2

ER -