title: Effect of ethylene glycol and polyethylene glycol on the acid-unfolded state of trypsinogen.
abstract: Effect of increasing concentrations of two of the polyols, ethylene glycol (EG) and polyethylene glycol (PEG), was studied by near and far circular dichroism (CD), fluorescence emission spectroscopy, and binding of hydrophobic dye, 1-anilino-8-naphthalene sulfonic acid (ANS). Far-UV CD spectra show the transition of acid-unfolded trypsinogen from an unordered state to an intermediate state having ordered secondary structure. Interestingly, near-UV CD spectra show some amounts of stabilizing effect on the tertiary structure of the protein also. Tryptophan fluorescence studies indicate the change in the environment of the tryptophan residues on addition of EG and PEG. Maximum ANS binding occurs in presence of 80% EG and 90% PEG (v/v), suggesting the presence of an intermediate or molten globule-like state at high concentrations of the two polyols.
authors.affiliation: Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh-202002, India.
authors.forename: Farah
authors.initials: F
authors.lastname: Naseem
authors.forename: Rizwan Hasan
authors.initials: RH
authors.lastname: Khan
mesh_terms: D000817:Anilino Naphthalenesulfonates / Q000737:chemistry; D002942:Circular Dichroism; D004795:Enzyme Stability; D019855:Ethylene Glycol / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D011092:Polyethylene Glycols / Q000494:pharmacology*; D011489:Protein Denaturation / Q000187:drug effects; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D013050:Spectrometry, Fluorescence; D014362:Trypsinogen / Q000737:chemistry* / Q000378:metabolism; D014364:Tryptophan / Q000737:chemistry
chemical_list: D000817:Anilino Naphthalenesulfonates; D011092:Polyethylene Glycols; C027132:1-anilino-8-naphthalenesulfonate; D014364:Tryptophan; D014362:Trypsinogen; D019855:Ethylene Glycol