A laccase with antiproliferative and HIV-I reverse transcriptase inhibitory activities from the mycorrhizal fungus Agaricus placomyces.

ABSTRACT: A novel 68?kDa laccase was purified from the mycorrhizal fungus Agaricus placomyces by utilizing a procedure that comprised three successive steps of ion exchange chromatography and gel filtration as the final step. The monomeric enzyme exhibited the N-terminal amino acid sequence of DVIGPQAQVTLANQD, which showed only a low extent of homology to sequences of other fungal laccases. The optimal temperature for A. placomyces laccase was 30°C, and optimal pH values for laccase activity towards the substrates 2,7'-azinobis[3-ethylbenzothiazolone-6-sulfonic acid] diammonium salt (ABTS) and hydroquinone were 5.2 and 6.8, respectively. The laccase displayed, at 30°C and pH 5.2, K(m) values of 0.392?mM towards hydroquinone and 0.775?mM towards ABTS. It potently suppressed proliferation of MCF 7 human breast cancer cells and Hep G2 hepatoma cells and inhibited human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) activity with an IC(50) of 1.8??M, 1.7??M, and 1.25??M, respectively, signifying that it is an antipathogenic protein.

SUBMITTER: Sun J 

PROVIDER: S-EPMC3471028 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature