Choline dehydrogenase of Pseudomonas aeruginosa A-16.

Studies on choline dehydrogenase have so far been restrickted to mammalian liver." In the microbial oxidation of choline, the conversion of choline to betaine has not been clarified enzymatically,2) though many bacteria can grow on choline as the sole carbon and nitrogen source.3) This paper deals with the choline dehydro genase of cell-free particulate preparations from Pseudomonas aeruginosa A-16 which catalyzes the first step of choline oxidation, in which betaine aldehyde is formed. Ps. aeruginosa A-16 was grown on medium of the following composition: choline, 15 g; yeast extract, 3 g; NaCl, 1 g; K3HPO4, 1 g; MgSO4.7H2O, 0.5 g; water to 1000 ml (pH 7.0). Cells were harvested by centrifugation after cultivation at 28C for 48 hr on a reciprocal shaker. Packed cells were washed once with