MAL 酪氨酸酶的优化：对棕色和黑色真黑素的抗癌活性

Optimization of MAL tyrosinase: anticancer activity for brown and black eumelanin.

作者信息

Gamal Shalaby Al Shimaa, Ragab Tamer I M, Helal Mohamed M I, Esawy Mona A

机构信息

Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Research Division, National Research Centre, Dokki, Cairo, Egypt.

出版信息

Heliyon. 2019 May 8;5(5):e01657. doi: 10.1016/j.heliyon.2019.e01657. eCollection 2019 May.

The influence of tyrosinase in catalyzes/stimulates the eumelanin production was studied. Accordingly, bacterial sp. was isolated and identified as based on 16S . It could grow and gave monophenolase and diphenolase productivity in medium contained tyrosin and Cu only. The tyrosinase enzymes were optimized by studying different environmental and nutritional factors. The maximum monophenolase and diphenolase productivity were obtained at 60 °C, pH9, Cu(0.01g), liver extract (1 g/L) and the oxygen level fixed at 20%. Also, the mannose as a carbon source increased the monophenolase production 6.2 times. For the first time, two types of eumelanin were extracted by hydrochloric acid treatment. The black and brown eumelanin weighed (0.1 g/100 mL and 0.7 g/100 mL respectively) and characterized by using FTIR and UV/Vis spectroscopy techniques. Their morphological structure and its elemental composition were characterized by SEM and EDAX respectively. The black melanin showed promising anticancer activity towards HEPG-2 and HCT-116 cell lines with IC values (6.15, 5.54 μg) compared to Doxorubicin (4.05, 4.45 μg) respectively.

研究了酪氨酸酶在催化/刺激真黑素生成中的作用。据此，分离出细菌菌株，并基于16S对其进行鉴定。它能够生长，并在仅含有酪氨酸和铜的培养基中产生单酚酶和二酚酶。通过研究不同的环境和营养因素对酪氨酸酶进行了优化。在60℃、pH9、铜（0.01g）、肝提取物（1g/L）且氧水平固定为20%的条件下，单酚酶和二酚酶的产量达到最高。此外，以甘露糖作为碳源可使单酚酶产量提高6.2倍。首次通过盐酸处理提取出两种类型的真黑素。黑色和棕色真黑素的重量分别为（0.1g/100mL和0.7g/100mL），并使用傅里叶变换红外光谱（FTIR）和紫外/可见光谱技术对其进行了表征。分别通过扫描电子显微镜（SEM）和能量散射X射线能谱仪（EDAX）对它们的形态结构及其元素组成进行了表征。与阿霉素（分别为4.05、4.45μg）相比，黑色黑色素对肝癌细胞系（HEPG - 2）和结肠癌细胞系（HCT - 116）显示出有前景的抗癌活性，其半数抑制浓度（IC）值分别为（6.15、5.54μg）。