Contains Zn2+ and Mg2+. Nicotinoprotein methanol dehydrogenases have a tightly bound NADP+/NADPH cofactor that does not dissociate during the catalytic process. Instead, the cofactor is regenerated by a second substrate or electron carrier. While the in vivo electron acceptor is not known, N,N-dimethyl-4-nitrosoaniline (NDMA) can serve this function in vitro. The enzyme has been detected in several Gram-positive methylotrophic bacteria, including Amycolatopsis methanolica, Rhodococcus rhodochrous and Rhodococcus erythropolis [1-3]. These enzymes are decameric, and possess a 5-fold symmetry [4]. Some of the enzymes can also dismutate formaldehyde to methanol and formate [5].