title: Purification and characterization of a Laccase with inhibitory activity toward HIV-1 reverse transcriptase and tumor cells from an edible mushroom (Pleurotus cornucopiae).
abstract: A 66-kDa laccase, with an N-terminal sequence different from those of other mushroom laccases, was purified from fresh fruiting bodies of the edible mushroom Pleurotus cornucopiae by using affinity chromatography on Affi-gel blue gel, ion exchange chromatography on Mono Q and gel filtration on Superdex 75. The procedure resulted in a 16-fold purification and a specific enzyme activity of 17.3 U mg(-1). The optimum pH and temperature for the purified laccase were pH 4 and 40 degrees C, respectively. This laccase inhibited proliferation of murine leukemia cell line L1210 and human hepatoma cell line HepG2, and reduced the activity of HIV-1 reverse transcriptase with an IC50 of 22 microM. There was neither mitogenic activity toward mouse splenocytes, nor hemagglutinating/hemolytic activity toward rabbit erythrocytes. This study yielded information about the potentially exploitable activities of P. cornucopiae laccase.
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
authors.forename: Jack Ho
authors.initials: JH
authors.lastname: Wong
authors.forename: Tzi Bun
authors.initials: TB
authors.lastname: Ng
authors.forename: Yun
authors.initials: Y
authors.lastname: Jiang
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.forename: S C
authors.initials: SC
authors.lastname: Sze
authors.forename: Kalin Yanbo
authors.initials: KY
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D054303:HIV Reverse Transcriptase / Q000037:antagonists & inhibitors*; D015497:HIV-1 / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D042845:Laccase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D020076:Pleurotus / Q000201:enzymology*; D011817:Rabbits; D018894:Reverse Transcriptase Inhibitors / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D018894:Reverse Transcriptase Inhibitors; D042845:Laccase; C514824:reverse transcriptase, Human immunodeficiency virus 1; D054303:HIV Reverse Transcriptase