Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.10.3.2 (laccase)
 4,656 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the metabolism of polycyclic aromatic hydrocarbons (PAHs) by using white rot fungi previously identified as organisms that metabolize polychlorinated biphenyls. Bran flakes medium, which has been shown to support production of high levels of laccase and manganese peroxidase, was used as the growth medium. Ten fungi grown for 5 days in this medium in the presence of anthracene, pyrene, or phenanthrene, each at a concentration of 5 microg/ml could metabolize these PAHs. We studied the oxidation of 10 PAHs by using laccase purified from Coriolopsis gallica. The reaction mixtures contained 20 microM PAH, 15% acetonitrile in 60 mM phosphate buffer (pH 6), 1 mM 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonate) (ABTS), and 5 U of laccase. Laccase exhibited 91% of its maximum activity in the absence of acetonitrile. The following seven PAHs were oxidized by laccase: benzo[a]pyrene, 9-methylanthracene, 2-methylanthracene, anthracene, biphenylene, acenaphthene, and phenanthrene. There was no clear relationship between the ionization potential of the substrate and the first-order rate constant (k) for substrate loss in vitro in the presence of ABTS. The effects of mediating substrates were examined further by using anthracene as the substrate. Hydroxybenzotriazole (HBT) (1 mM) supported approximately one-half the anthracene oxidation rate (k = 2.4 h(-1)) that ABTS (1 mM) supported (k = 5.2 h(-1)), but 1 mM HBT plus 1 mM ABTS increased the oxidation rate ninefold compared with the oxidation rate in the presence of ABTS, to 45 h(-1). Laccase purified from Pleurotus ostreatus had an activity similar to that of C. gallica laccase with HBT alone, with ABTS alone, and with 1 mM HBT plus 1 mM ABTS. Mass spectra of products obtained from oxidation of anthracene and acenaphthene revealed that the dione derivatives of these compounds were present.
 ...
PMID:Polycyclic aromatic hydrocarbon metabolism by white rot fungi and oxidation by Coriolopsis gallica UAMH 8260 laccase. 1047 79

The metabolism of polycyclic aromatic hydrocarbons (PAHs) was studied in vivo and in vitro in systems consisting of Rigidoporus lignosus and its laccase, in the presence of so-called "mediator" compounds. The static culture of the native fungal strain was able to metabolize anthracene and 2-methylanthracene, but not 9-nitroanthracene. The addition of redox mediators 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 1-hydroxybenzotriazole (HBT) or violuric acid (VA) led to a significant increase in the degradation of substrates. The oxidation of PAHs was not significant when purified laccase was used without the addition of mediators. The addition of these compounds increased the oxidation of all substrates by approximately 70-80% after 72 h of incubation. The degradation rate was highest for 2-methylanthracene in the presence of VA.
 ...
PMID:Degradation of polycyclic aromatic hydrocarbons by Rigidoporus lignosus and its laccase in the presence of redox mediators. 1835 Mar 82