title: Biophysical studies of an NAD(P)(+)-dependent aldehyde dehydrogenase from Bacillus licheniformis.
abstract: Aldehyde dehydrogenase (ALDH) catalyzes the conversion of aldehydes to the corresponding acids by means of an NAD(P)(+)-dependent virtually irreversible reaction. In this investigation, the biophysical properties of a recombinant Bacillus licheniformis ALDH (BlALDH) were characterized in detail by analytical ultracentrifuge (AUC) and various spectroscopic techniques. The oligomeric state of BlALDH in solution was determined to be tetrameric by AUC. Far-UV circular dichroism analysis revealed that the secondary structures of BlALDH were not altered in the presence of acetone and ethanol, whereas SDS had a detrimental effect on the folding of the enzyme. Thermal unfolding of this enzyme was found to be highly irreversible. The native enzyme started to unfold beyond ~0.2 M guanidine hydrochloride (GdnHCl) and reached an unfolded intermediate, [GdnHCl](05, N-U), at 0.93 M. BlALDH was active at concentrations of urea below 2 M, but it experienced an irreversible unfolding under 8 M denaturant. Taken together, this study provides a foundation for the future structural investigation of BlALDH, a typical member of ALDH superfamily enzymes.
authors.affiliation: Department of Food Science and Technology, Hungkuang University, Shalu, Taichung City, Taiwan.
authors.forename: Huei-Fen
authors.initials: HF
authors.lastname: Lo
authors.forename: Jian-Yu
authors.initials: JY
authors.lastname: Su
authors.forename: Hsiang-Ling
authors.initials: HL
authors.lastname: Chen
authors.forename: Jui-Chang
authors.initials: JC
authors.lastname: Chen
authors.forename: Long-Liu
authors.initials: LL
authors.lastname: Lin
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D001407:Bacillus / Q000201:enzymology*; D055592:Biophysical Phenomena; D002942:Circular Dichroism; D019791:Guanidine / Q000494:pharmacology; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary / Q000187:drug effects; D058767:Protein Unfolding / Q000187:drug effects; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D012997:Solvents / Q000494:pharmacology; D013050:Spectrometry, Fluorescence; D013696:Temperature; D014364:Tryptophan; D014461:Ultracentrifugation; D014508:Urea / Q000494:pharmacology
chemical_list: D012997:Solvents; D012967:Sodium Dodecyl Sulfate; D014364:Tryptophan; D014508:Urea; D000444:Aldehyde Dehydrogenase; D019791:Guanidine