Purification and characterization of 4-N-trimethylamino-1-butanol dehydrogenase from Fusarium merismoides var. acetilereum

Abstract

From investigation of 60 filamentous fungi, we identified Fusarium merismoides var. acetilereum, which uses 4-N-trimethylamino-1-butanol (TMA-butanol) as the sole source of carbon and nitrogen. The fungus produced NAD(+)-dependent TMA-butanol dehydrogenase (DH) when it was cultivated in medium containing TMA-butanol. The enzyme showed molecular mass of 40 kDa by SDS-PAGE and 160 kDa by gel filtration, suggesting that it is a homotetramer. TMA-butanol DH is stable at pH 7.5-9.0. It exhibits moderate stability with respect to temperature (up to 30 °C). Additionally, it has optimum activity at 45 °C and at pH 9.5. The enzyme has broad specificity to various alkyl alcohols and amino alkyl alcohols, and the carbon chains of which are longer than butanol. Moreover, the activity is strongly inhibited by oxidizing agents, carbonyl and thiol modulators, and chelating agents. This report is the first study examining TMA-butanol DH from eukaryotic microbes.