PQQ is a new cofactor, scientifically known as pyrroloquinoline quinone. It is the third cofactor discovered in membrane bound bacterial dehydrogenase after flavin nucleotides (FMN, FAD) and nicotinamide nucleotides (MAD, NADP), and is known as the 104th vitamin in the world medical community. PQQ not only participates in redox reactions in organisms, but also has some special biological activities and physiological functions