Dimethylsulfoxide dehydrogenase

Figure 17.8 Catal3ftic zinc center of horse liver alcohol dehydrogenase revealed from an X-ray crystallographic structure (PDB file 20HX) [Al-Karadaghi et al., 1994]. The bound NADH cofactor, a molecule of the inhibitor dimethylsulfoxide (DMSO), and the amino acid residues that coordinate the Zn are shown as sticks shaded according to the elements, and the Zn center is shown as a gray sphere, while the protein is shown in thin gray lines.

Sutton [1.15] studied the question of how quickly solutions with certain CPAs (GL, dimethylsulfoxide (DMSO) and others] have to be cooled in order to avoid crystallization. At 100 °C/min concentration of 42.1 % DMSO and 48.5 % for GL are necessary to achieve the glass phase. With a 32.5 % solution of (2R.3R)-(-)butan-2,3-dio, the same effect can be accomplished at = 50 °C/min. In Fig. 1.18 Sutton (Fig. 11 from [1.114]) showed, that polyethylene glycol with a molecular weight of 400 (PEG 400) reduced the critical cooling rate down to approx. 25 °C/min. The addition of PEG 8000 [1.115] improved the protection of lactate dehydrogenase (LDH) by maltodextrins, if maltodextrins with low dextrose equivalents are used. 

Members of the dimethylsulfoxide (DMSO) reductase family have the molybdenum ligated by two MPTs, one 0x0 group, and the donor atom from the side chain of an amino acid residue—O7 of a serinyl residue (DMSO reductase or trimethylamineoxide (TMAO) reductase), S7 of a cysteinyl residue (dissimilatory nitrate reductase), or Sc7 of selenocys-teinyl residue (formate dehydrogenase). 

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