Collect. Czech. Chem. Commun. 1992, 57, 641-655

Effect of Methanol on the Structure of Human Blood Serum Orosomucoid (Acid α1-Glycoprotein)

Vladimír Karpenkoa, Ludmila Šinkorováa and Milan Kodíčekb

a Department of Physical Chemistry, Faculty of Natural Sciences, Charles University, Albertov 2030, 128 40 Prague 2
b Department of Biochemistry and Microbiology, Prague Institute of Chemical Technology, Technická 3, 166 28 Prague 6


The effect of methanol (volume fraction 0-70%) on the optical properties of human blood serum orosomucoid (acid α1-glycoprotein) was studied over the pH range 5-12. The changes of these properties were correlated with the concept of three-dimensional arrangement of the orosomucoid molecule as obtained by a prediction study based on refined conformational preferences. From a complex analysis of the data obtained following conclusions on the orosomucoid structure in solution could be made: 1) α-helix content increases at constant pH with the methanol volume fraction exceeding 30%. 2) α-helix content at constant methanol concentration is maximal at pH 9-10. 3) The changes in conformation brought about by the presence of methanol result in the masking of 1 tyrosine and 1-tryptophan residue in 70% alcohol. It has been observed that the complex action of even the lowest alcohol leads to marked changes at the various levels of the three-dimensional organization of the orosomucoid molecule.