A simple preparative method was developed for purification of Tyrosinase from edible mushroom (Agaricus bispora). A homogenized extract of mushroom was first saturated by ammonium sulfate. The desired precipitate was mixed thoroughly with DEAE-Cellulose (DE-52) and washed out to produce melanin free precipitate. The obtained protein solution was dialyzed against running water for 4 hrs, then, concentrated and chromatographed on a DE-52 column. On the basis of the activities assay, the eluted fractions by 150 mM salt solution were selected for further purification. The collected fractions were pooled and chromatographed on a Sephadex G-200 column. Polyacrylamide gel electrophoresis (PAGE) of the purified tyrosinase produced a single band right beside the commercial sample obtained from Sigma Company at 128 kDa. The lyophilized form of the purified Tyrosinase had a purification degree of 104 and showed strong cresolase and catecholase activities when compared to a commerically available tyrosinase.

Background: Mycetismus or mushroom poisoning is an important health concern and a potentially fatal state that usually occurs after incidental ingestion of mushroom’s sexual organs or fruiting bodies of fungus among the mycologists and the one who desire a natural or organic diet. The vast majority of mortality due to mushroom poisonings is attributed to fungus belonging to genus Amanita.Materials and methods: This report describes 34 cases with A. phalloides mushroom poisoning regarding the epidemiological presentation, clinical manifestation and laboratory findings. These patients were admitted in three hospitals of Tabriz University of Medical Sciences during 1989-1994.Results: The age of victims ranged from 4-75 years. Diagnosis of A. phalloides mushroom poisoning was confirmed by mycologist in 12 cases, toxicological studies in 5 cases and combined mycological and toxicological approaches in 3 cases. It was only suspected in 14 cases as the patients had died before being admitted or immediately after hospitalization. Ingestion of doubtful mushrooms was found either in their histories or mushrooms poisoning was documented in their relatives. Most of the victims (68%) were affected in spring, while no case was reported in summer. Conclusion: Mushroom poisoning should be considered in differential diagnosis of any case of acute gastroenteritis, especially during spring and fall when moderate temperature and moist conditions facilitate mushroom’s growth.