Oxidative biodegradation of phosphorothiolates by fungal laccase.
Organophosphorus (OP) insecticides and nerve agents that contain P-S bond are relatively more resistant to enzymatic hydrolysis. Purified phenol oxidase (laccase) from the white rot fungus Pleurotus ostreatus (Po) together with the mediator 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) (ABTS) displayed complete and rapid oxidative degradation of the nerve agents VX and Russian VX (RVX) and the insecticide analog diisopropyl-Amiton with specific activity: k(sp) = 2200, 667 and 1833 nmol min(-1) mg(-1), respectively (pH 7.4, 37 degrees C). A molar ratio of 1:20 for OP/ABTS and 0.05 M phosphate at pH 7.4 provided the highest degradation rate of VX and RVX. The thermostable laccase purified from the fungus Chaetomium thermophilium (Ct) in the presence of ABTS caused a 52-fold slower degradation of VX with k(sp) = 42 nmol min(-1) mg(-1). The enzymatic biodegradation products were identified by 31P-NMR and GC/MS analysis.
Amitai
G
G
Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona. amitai@iibr.gov.il
Adani
R
R
Sod-Moriah
G
G
Rabinovitz
I
I
Vincze
A
A
Leader
H
H
Chefetz
B
B
Leibovitz-Persky
L
L
Friesem
D
D
Hadar
Y
Y
D052160:Benzothiazoles; D001673:Biodegradation, Environmental; D007306:Insecticides / Q000378:metabolism*; D007700:Kinetics; D042845:Laccase; D009943:Organophosphorus Compounds / Q000378:metabolism*; D009946:Organothiophosphorus Compounds; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism*; D020076:Pleurotus / Q000201:enzymology* / Q000254:growth & development; D013379:Substrate Specificity; D013451:Sulfonic Acids / Q000378:metabolism
D052160:Benzothiazoles; D007306:Insecticides; D009943:Organophosphorus Compounds; D009946:Organothiophosphorus Compounds; D013451:Sulfonic Acids; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; C003415:amiton; D010088:Oxidoreductases; D042845:Laccase