Methoxatin (PQQ) in guinea-pig neutrophils

  • Free Radic Biol Med. 1994 Oct;17(4):311-20. doi: 10.1016/0891-5849(94)90017-5.
A Bishop  1 ,  M A Paz ,  P M Gallop ,  M L Karnovsky
Affiliations
  • 1. Department of Genetics, Harvard Medical School, Harvard School of Dental Medicine, Boston, MA.
PMID: 8001835 DOI: 10.1016/0891-5849(94)90017-5
Abstract

PQQ, also called methoxatin, has been isolated from guinea-pig neutrophils. The organic cations diphenyleneiodonium (DPI) and diphenyliodonium (BPI) and the aromatic o-diamine 4,5-dimethylphenylenediamine (DIMPDA) sequester synthetic PQQ and inhibit its redox-cycling activity in a model system. Standards were made of adducts of tritiated PQQ with unlabeled DIMPDA and of unlabeled PQQ with tritiated DPI or DIMPDA. PQQ adducts were isolated from guinea-pig neutrophils with each of the tritiated inhibitors. They were separated and defined by high-performance liquid chromatography (HPLC). Tiron, a disodium benzene disulphonic acid, broke the DPI-PQQ adduct isolated from neutrophils and released free PQQ. Both DPI and DIMPDA, as well as BPI, blocked O2.- release by stimulated neutrophils. The blockade exerted by these inhibitors was released by the addition of PQQ to the cell suspensions. The data demonstrate the presence of PQQ in guinea-pig neutrophils and suggest that it has a possible role, direct or indirect, in the O2.(-)-producing respiratory burst.

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