Quasi-vitamins: Pyrroloquinoline Quinone Domina Petric, MD

Chemical nature Pyrroloquinoline quinone (PQQ), sometimes called methoxatin, is a tricarboxylic acid with a fused heterocyclic (o-quinone) ring system. Its C-5 carbonyl group is very reactive toward nucleophiles, leading to adduct formation. 11/21/2018 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008.

Dietary sources egg yolk adrenal tissue citrus fruits casein starch Some reports indicate PQQ to be present in: egg yolk adrenal tissue citrus fruits casein starch isolated soy protein 11/21/2018 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008.

Metabolic functions In bacterial quinoproteins, PQQ is covalently bound to the apoprotein, probably by an amide or ester bond via its carboxylic acid group(s). The redox behavior of PQQ involves its ability to form adducts that facilitate both one- and two-electron transfers. 11/21/2018 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008.

Metabolic functions The role of PQQ in eukaryotes is less clear. One important enzyme that has been proposed to be a quinoprotein is lysyl oxidase. Lysyl oxidase plays a key role in the crosslinking of collagen and elastin by catalyzing the oxidative deamination of peptidyllysine to peptidyl- α-aminoadipic-δ-semialdehyde. 11/21/2018 Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008.

Literature Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc. 2008. 11/21/2018