Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:1.10.3.2 (
laccase
)
4,656
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Previously, we hypothesized that microbial
laccase
oxidizes iodide (I
-
) in soils to molecular iodine (I
2
) or hypoiodous acid (HIO), both of which are easily incorporated into natural soil organic matter, and thus plays a role in iodine sorption on soils. In this study, soil iodide oxidase activity was determined by a colorimetric assay to evaluate if
laccase
is responsible for iodide oxidation in soils. Three types of Japanese soil showed significant iodide oxidase activities (0.751-2.87 mU g soil
-1
) at pH 4.0, which decreased with increasing pH, until it was no longer detected at pH 5.5. The activity was inhibited strongly by autoclaving or by the addition of common
laccase
inhibitors. Similar tendency of inhibition was observed in soil
laccase
activity, which was determined with 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as a substrate. Significant positive correlations (R
2
values of 0.855-0.896) between iodide oxidase activity and
laccase
activity were observed in two of three soils. Commercially available fungal laccases showed only very low iodide oxidase activities (4.68-18.0 mU mg
-1
), but enhanced activities of 102-739 mU mg
-1
were observed in the presence of redox mediators. Finally, we successfully isolated fungal strains with iodide-oxidizing phenotype in the presence of redox mediators. Polyacrylamide gel electrophoresis of the culture supernatant of Scytalidium sp. strain
UMS
and subsequent active stain revealed that the fungal
laccase
actually oxidized iodide in the presence of redox mediators. These results suggest that at least part of iodide in soils is oxidized by fungal
laccase
through the
laccase
-mediator system.
...
PMID:Role of fungal laccase in iodide oxidation in soils. 2966 75
