X-ray crystallographic studies of two bacterial quinoproteins. Methylamine Dehydrogenase and Quinohaemoprotein Alcohol Dehydrogenase

For the catalysis of reactions involving the transfer of electrons enzymes utilize either metal ions or special organic compounds called cofactors. A group of enzymes, known as quinoproteins, makes use of cofactors that contain a quinone function. This quinone function enables quinoproteins to oxidize a wide range of substrates, including amines, alcohols and sugars. During catalysis two electrons are transferred from the substrate to the quinone cofactor. Until recently, all quinoproteins were thought to contain the cofactor pyrroloquinoline quinone (PQQ). However, a number of recent discoveries have shown that besides PQQ at least two other cofactors containing a quinone function are used by quinoproteins. A review of recent developments in the field of quinoproteins and a summary of the current knowledge about this class of proteins is presented in Chapter 1 . Zie: Summary