1. Quasi-vitamins: Pyrroloquinoline Quinone
Domina Petric, MD

2. 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

3. 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

4. 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

5. 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

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