Covalently bound pyrroloquinoline quinone is the organic prosthetic group in human placental lysyl oxidase.
Treatment of purified human placental lysyl oxidase with 2,4-dinitrophenylhydrazine (DNPH) resulted in a large spectral change and inhibition of enzyme activity. Proteolytic degradation of the derivatized enzyme yielded only one single coloured product, which was spectrally and chromatographically identical with the C-5 hydrazone of PQQ (pyrroloquinoline quinone) and DNPH. Since this represents the first example of a PQQ-containing enzyme in man, possible implications of the finding are discussed.
D000594:Amino Acid Oxidoreductases / Q000378:metabolism*; D003067:Coenzymes / Q000378:metabolism*; D006801:Humans; D045542:PQQ Cofactor; D010659:Phenylhydrazines / Q000494:pharmacology; D010920:Placenta / Q000201:enzymology*; D008249:Protein-Lysine 6-Oxidase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011804:Quinolines / Q000378:metabolism*; D013053:Spectrophotometry
D003067:Coenzymes; D010659:Phenylhydrazines; D011804:Quinolines; C004787:2,4-dinitrophenylhydrazine; D045542:PQQ Cofactor; D000594:Amino Acid Oxidoreductases; D008249:Protein-Lysine 6-Oxidase