Quinoprotein-dependent Periplasmic Oxidase System.

Identification in Marinomonas mediterranea of a novel quinoprotein with glycine oxidase activity

A novel enzyme with lysine-epsilon oxidase activity was previously described in the marine bacterium Marinomonas mediterranea. This enzyme differs from other l-amino acid oxidases in not being a flavoprotein but containing a quinone cofactor. It is encoded by an operon with two genes lodA and lodB. The first one codes for the oxidase, while the second one encodes a protein required for the expr...

Modeling of quinoprotein functions

A b s t r a c t : The model compound of TTQ (tryptophan tryptophylquinone), the active site cofactor of bacterial methylamine dehydrogenases, was synthesized for the first time. 1H NMR analysis and theoretical calculations on the model compound (1) indicate that its molecular geometry is close to that of TTQ in the enzyme active site. The redox potential and spectral characteristics (W-vis and ...

Quinoprotein-catalysed reactions.

This review is concerned with the structure and function of the quinoprotein enzymes, sometimes called quinoenzymes. These have prosthetic groups containing quinones, the name thus being analogous to the flavoproteins containing flavin prosthetic groups. Pyrrolo-quinoline quinone (PQQ) is non-covalently attached, whereas tryptophan tryptophylquinone (TTQ), topaquinone (TPQ) and lysine tyrosylqu...

NADPH oxidase 4-dependent pathway

Role of NADP-dependent and quinoprotein glucose dehydrogenases in gluconic acid production by G luconobacter oxydans

Gluconobacter oxydans, an organism used for the industrial production of gluconic acid, contains two glucose dehydrogenases (GDHs) catalysing the direct oxidation of glucose to gluconic acid. In addition to a quinoprotein (PQQ-dependent), membrane-bound GDH (EC 1.1.99.17), an NADP-dependent, cytoplasmic GDH is present. From three types of experiments, evidence is presented that the quinoprotein...