Advances in Quinoprotein Research

Quinoproteins, sometimes called quinoenzymes, are oxidoreductase whose catalytic mechanisms involve quinone-containing prosthetic groups in their active sites. Among these quinone cofacters, pyrrolo-quinoline quinone(PQQ) is most typical, along with tryptophan tryptophylquinone(TTQ), topaquinone(TPQ) and lysine tyrosylquinone(LTQ). PQQ-dependent quinoproteins are classified into three groups, typesⅠ,Ⅱ, and Ⅲ. TypeⅠ quinoprotein is a simple quinoprotein having PQQ as the only prosthetic group, while typeⅡ and typeⅢ are quinohemoprotein having heme c as well as PQQ in the catalytic polypeptide. In this article, some typical quino(hemo)proteins are summarized, and their structures and functions and application aspects are disscussed.