桑黄发酵液中凝集素SHL24的分离与生物活性研究

Isolation and bioactive characters of a novel lectin SHL24 from the liquid fermentation of Phellinus baumii

【背景】桑黄是一种具有很高药用价值及广泛应用前景的药用真菌,其主要有效成分为多糖。凝集素则是桑黄所含的另一类生物活性物质,具有免疫调节、抗肿瘤及抗菌等作用。【目的】从药用真菌桑黄发酵液中分离纯化凝集素SHL24,并对其生物活性进行初步探究。【方法】通过冷冻干燥、Sephadex G-50、DEAE Sephadex A-25、MPLC-MonoQ和LPLC-Sephadex G-75等方法,从药用真菌桑黄的发酵液中进行分离纯化;利用LPLC-Sephadex G-75和SDS-PAGE凝胶电泳鉴定其分子质量;检测不同pH、金属离子、糖、发酵时间、血红细胞、温度对其凝血活性的影响。【结果】从药用真菌桑黄发酵液中分离到单一蛋白条带,SDS-PAGE凝胶电泳检测其分子质量约为24 kD,与分子筛层析法分析的分子质量一致,表明该凝集素为单亚基蛋白。SHL24可以凝集供试的小鼠血红细胞和4种血型人血的血红细胞,但对不同来源的血红细胞凝集程度不同。糖抑制试验表明,SHL24不被D-甘露糖、D-麦芽糖、葡萄糖、蔗糖、树胶醛糖、D-乳糖以及L-鼠李糖所抑制。热稳定性试验和金属离子对SHL24凝血活性影响试验表明SHL24具有较好的热稳定性且其凝血活性不受Ca^(2+)、Mg^(2+)和Zn^(2+)等二价阳离子的影响。【结论】SHL24具有的稳定理化性质和生物活性,有作为蛋白质药物的潜质。

[Background] Phellinus baumii is a fungus with a high medicinal value and wide application prospect. The main active ingredient of Phellinus baumii is polysaccharide. Besides, lectin is another physiologically active substance which has the functions of immunomodulation, anti-tumor and antibacterial. [Objective] A novel lectin, SHL24, is isolated and purigied from the liquid fermentation of medicinal fungus Phellinus baumii and its bioactivity is studied. [Methods] Sephadex G-50, DEAE Sephadex A-25, MPLC-MonoQ and LPLC-Sephadex G-75 were used to purify this lectin. The molecular mass was determined by SDS-PAGE and LPLC-Sephadex G-75. The effects of different pH, metal ions, sugars, fermentation times, red blood cells, and temperatures on coagulation activity were studied. [Results] SHL24 is a single-subunit protein with the relative molecular weight of 24 kD. SHL24 can agglutinate red blood cells of mouse and human, while it has a variety of activities for different resources of red blood cells. SHL24 cannot be inhibited by D-mannose, D-maltose, dextrose, cane sugars, D-lactose, arabinose and L-rhamnose. SHL24 has good thermal stability and its coagulation activity isn＇t inhibited by cations, such as Ca2＋, Mg2＋ and Zn2＋. [Conclusion] The stable physical-chemical properties and biological activity of SHL24 make it worth to further study on its pharmacological action.