Regulation and Expression of Bacterial Quinoproteins

Abstract

Bacterial quinoproteins are found in a variety of bacteria that represent a wide range of metabolic types. For three of these proteins—methanol dehydrogenase (MDH), methylamine dehydrogenase (MADH), and glucose dehydrogenase (GDH)—information is available concerning regulatory parameters. In this chapter, the authors discuss the current evidence concerning regulation and expression of MDH, MADH, and GDH. From the data so far accumulated it appears that the serine or RuMP pathway methylotrophs follow different regulatory strategies for MDH synthesis than the autotrophic methylotrophs. In serine and RuMP pathway methylotrophs, MDH serves to generate both ATP and formaldehyde. The bacteria that contain MADH are capable of using alternate carbon, energy, and nitrogen sources. In all cases, MADH activity has been shown to be present in cells grown on methylamine as the sole carbon and energy source but at reduced or nondetectable levels in cells grown on other substrates such as methanol, succinate, or glucose.