title: The inhibition of glyceradehyde-3-phosphate dehydrogenase by benz(a)anthracene and its derivatives after exposure to laboratory lighting.
abstract: Colloidal dispersions of polycyclic aromatic hydrocarbons were found to inhibit glyceraldehyde-3-phosphate dehydrogenase (GPDH) and lactic acid dehydrogenase (LDH) after a short exposure of the incubation medium to laboratory lighting. The activation effect was observed with substituted 7-methyl derivatives of 12-methylbenz(a)anthracene also. One minute exposure of 7-methoxymethyl-12-methylbenz(a)anthracene (MeO-DMBA) to light was sufficient to produce a measurable amount of GPDH inhibition. The rate of enzyme inhibition was related to the pH of the dispersion. A small but significant effect of light on the inhibition of the enzymes by K-region epoxides was seen. Protein binding of the epoxides was not well correlated with the inhibition. The light effect was oxygen-dependent and was related to the hydrocarbon concentration. The active form decayed over a period of more than 25 days. The necessity for protecting reactions involving hydrocarbons and their derivatives from light is emphasized.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001551:Benz(a)Anthracenes / Q000494:pharmacology*; D001665:Binding Sites; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000037:antagonists & inhibitors*; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008027:Light; D009132:Muscles / Q000201:enzymology; D010100:Oxygen; D010446:Peptide Fragments / Q000032:analysis; D011485:Protein Binding; D011817:Rabbits; D013329:Structure-Activity Relationship; D013997:Time Factors; D014357:Trypsin
chemical_list: D000596:Amino Acids; D001551:Benz(a)Anthracenes; D010446:Peptide Fragments; D007770:L-Lactate Dehydrogenase; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D014357:Trypsin; D010100:Oxygen