Yehia Ramy Sayed
Department of Botany Faculty of Science Cairo University Giza Egypt.
Braz J Microbiol. 2014 May 19;45(1):127-33. doi: 10.1590/S1517-83822014005000026. eCollection 2014.
Manganese peroxidase (MnP) was produced from white rot edible mushroom Pleurotus ostreatus on the culture filtrate. The enzyme was purified to homogeneity using (NH4)2SO4 precipitation, DEAE-Sepharose and Sephadex G-100 column chromatography. The final enzyme activity achieved 81 U mL(-1), specific activity 78 U mg(-1) with purification fold of 130 and recovery 1.2% of the crude enzyme. SDS-PAGE indicated that the pure enzyme have a molecular mass of approximately 42 kDa. The optimum pH was between 4-5 and the optimum temperature was 25 °C. The pure MnP activity was enhanced by Mn(2+), Cu(2+), Ca(2+) and K(+) and inhibited by Hg(+2) and Cd(+2). H2O2 at 5 mM enhanced MnP activity while at 10 mM inhibited it significantly. The MnP-cDNA encoding gene was sequenced and determined (GenBank accession no. AB698450.1). The MnP-cDNA was found to consist of 497 bp in an Open Reading Frame (ORF) encoding 165 amino acids. MnP from P. ostreatus could detoxify aflatoxin B1 (AFB1) depending on enzyme concentration and incubation period. The highest detoxification power (90%) was observed after 48 h incubation at 1.5 U mL(-1) enzyme activities.
锰过氧化物酶（MnP）由白腐食用菌平菇在培养滤液中产生。使用硫酸铵沉淀、DEAE-琼脂糖和葡聚糖G-100柱色谱法将该酶纯化至同质。最终酶活性达到81 U mL(-1)，比活性为78 U mg(-1)，纯化倍数为130，粗酶回收率为1.2%。SDS-PAGE表明纯酶的分子量约为42 kDa。最适pH在4-5之间，最适温度为25℃。纯MnP活性被Mn(2+)、Cu(2+)、Ca(2+)和K(+)增强，被Hg(+2)和Cd(+2)抑制。5 mM的H2O2增强MnP活性，而10 mM时则显著抑制其活性。对编码MnP的cDNA基因进行了测序和测定（GenBank登录号：AB698450.1）。发现MnP-cDNA在一个开放阅读框（ORF）中由497 bp组成，编码165个氨基酸。平菇的MnP可以根据酶浓度和孵育时间对黄曲霉毒素B1（AFB1）进行解毒。在1.5 U mL(-1)酶活性下孵育48 h后，观察到最高解毒能力（90%）。
