Pyrroloquinoline Quinone a Redox Cofactor and Its Involvement in Biological System

This paper highlights some features, which describe the characterization and physiological importance of Pyrroloquinoline quinone (PQQ), discovered more than forty years ago. Mechanism of biosynthetic pathway of PQQ is described based on sequence analysis and homology models. But still now all activities of PQQ are not discovered. PQQ is not only a bacterial redox cofactor in alcohol oxidation catalysed by alcohol dehydrogenase enzyme, it is also considered as a redox cofactor for mammals also. Among physiological importance of PQQ, it shows antioxidant property, cardioprotection, neuro protection, improvement of neonatal growth and reproductive performance. It acts as a microbial stimulant and reduces the lag phase of long generation time strains. PQQ takes part in the oxidation process of glucose metabolism also. In mitochondriogenesis cell signaling pathway PQQ play an important role. The controversy, that whether it should be considered as a vitamin or not still remains. But it has various physiological roles in biological system.