Probing structural changes of proteins incorporated into water-in-oil emulsions
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Probing structural changes of proteins incorporated into water-in-oil emulsions. / Jorgensen, Lene; van de Weert, Marco; Vermehren, Charlotte; Bjerregaard, Simon; Frokjaer, Sven.
In: Journal of Pharmaceutical Sciences, Vol. 93, No. 7, 07.2004, p. 1847-59.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Probing structural changes of proteins incorporated into water-in-oil emulsions
AU - Jorgensen, Lene
AU - van de Weert, Marco
AU - Vermehren, Charlotte
AU - Bjerregaard, Simon
AU - Frokjaer, Sven
N1 - Copyright 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93:1847-1859, 2004
PY - 2004/7
Y1 - 2004/7
N2 - The applicability of different techniques, that is, Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), and intrinsic tryptophan fluorescence, for probing the structural changes of proteins in the water-in-oil emulsions are investigated using nondefatted bovine (BSA) and human serum albumin (HSA) as model proteins. FTIR shows that the overall secondary structure of the proteins changes to some extent, 12% for BSA and 9% for HSA, when these are incorporated into the emulsion. There was no evidence of changes in the distribution of secondary structural elements apart from the changes in overall secondary structure. A blue shift of 12 to 14 nm in the fluorescence emission maximum was observed for proteins in the emulsion and 3 to 11 nm in the simulated interior of the aqueous phase, thus indicating structural changes around the tryptophan residues. DSC scans indicated that the domains in the proteins change because the shape of the transition peaks changes, when the proteins were incorporated into the emulsions. The total enthalpy decreases for BSA and HSA when these are incorporated into the emulsion, and some changes to the transition temperatures are observed. All the applied techniques supplement each other to give a more complete picture of the structural changes in proteins in intact water-in-oil emulsions.
AB - The applicability of different techniques, that is, Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), and intrinsic tryptophan fluorescence, for probing the structural changes of proteins in the water-in-oil emulsions are investigated using nondefatted bovine (BSA) and human serum albumin (HSA) as model proteins. FTIR shows that the overall secondary structure of the proteins changes to some extent, 12% for BSA and 9% for HSA, when these are incorporated into the emulsion. There was no evidence of changes in the distribution of secondary structural elements apart from the changes in overall secondary structure. A blue shift of 12 to 14 nm in the fluorescence emission maximum was observed for proteins in the emulsion and 3 to 11 nm in the simulated interior of the aqueous phase, thus indicating structural changes around the tryptophan residues. DSC scans indicated that the domains in the proteins change because the shape of the transition peaks changes, when the proteins were incorporated into the emulsions. The total enthalpy decreases for BSA and HSA when these are incorporated into the emulsion, and some changes to the transition temperatures are observed. All the applied techniques supplement each other to give a more complete picture of the structural changes in proteins in intact water-in-oil emulsions.
KW - Animals
KW - Calorimetry, Differential Scanning
KW - Cattle
KW - Emulsions
KW - Humans
KW - Oils
KW - Protein Structure, Secondary
KW - Serum Albumin
KW - Water
U2 - 10.1002/jps.20097
DO - 10.1002/jps.20097
M3 - Journal article
C2 - 15176072
VL - 93
SP - 1847
EP - 1859
JO - Journal of Pharmaceutical Sciences
JF - Journal of Pharmaceutical Sciences
SN - 0022-3549
IS - 7
ER -
ID: 44640658