Model molecules for the active centre of alcoholdehydrogenases--an FT-IR study.
We synthesized a triamide of Kemp's acid with two cysteine groups and one histidine group (compound 1), and a triamide of 1,3,5-pentane tricarboxylic acid with tyrosine, histidine, and arginine molecules (compound 2). From compound 1 we obtained the hydrated Zn2+ complex, compound 3. The FT-IR spectra of various complexes of compounds 1-3 with NAD+ show no IR continua and hence, no hydrogen-bonded chains with proton polarizability are present. In the case of the complex (compounds 2 and 3 and NAD+) an intense continuum demonstrates that a hydrogen-bonded chain is formed with large proton polarizability due to collective proton motion. This proton pathway is discussed. The O atom of the nicotinamide group of NAD+ is a strong hydrogen bond acceptor. This result is discussed with regard to the catalytic mechanism.
Brzezinski
B
B
Faculty of Chemistry, Adam Mickiewicz University, Poznan, Poland.
Urjasz
H
H
Zundel
G
G
Bartl
F
F
D000426:Alcohol Dehydrogenase / Q000737:chemistry*; D001665:Binding Sites; D006860:Hydrogen Bonding; D008958:Models, Molecular; D009243:NAD / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
D009243:NAD; D000426:Alcohol Dehydrogenase