Effects of Ca2+ on the activity and stability of methanol dehydrogenase.
The effects of exogenously added Ca2+ on the enzymatic activity and structural stability of methanol dehydrogenase were studied for various Ca2+ concentrations. Methanol dehydrogenase activity increased significantly with increasing concentration of Ca2+, approaching saturation at 200 mM Ca2+. The effect of Ca2+ on the activation of MDH was time dependent and Ca2+ specific and was due to binding of the metal ions to the enzyme. Addition of increasing concentration of Ca2+ caused a decrease of the intrinsic tryptophan fluorescence intensity in a concentration-dependent manner to a minimum at 200 mM, but with no change in the fluorescence emission maximum wavelength or the CD spectra. The results revealed that the activation of methanol dehydrogenase by Ca2+ occurred concurrently with the conformational change. In addition, exogenously bound Ca2+ destabilized MDH. The potential biological significance of these results is discussed.
Zhao
Y
Y
Department of Biochemistry and Biophysics, College of Life Scineces, Wuhan University, China.
Wang
G
G
Cao
Z
Z
Wang
Y
Y
Cheng
H
H
Zhou
H M
HM
D000429:Alcohol Oxidoreductases / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology*; D002384:Catalysis; D004789:Enzyme Activation; D004795:Enzyme Stability; D020580:Methylobacterium / Q000201:enzymology*; D011487:Protein Conformation / Q000187:drug effects; D013050:Spectrometry, Fluorescence; D013997:Time Factors
D000429:Alcohol Oxidoreductases; C019641:alcohol dehydrogenase (acceptor); D002118:Calcium