色氨酸及其衍生物对海南粗榧悬浮细胞合成三尖杉酯类碱的影响

Effect of L-tryptophan and its derivatives on cephalotaxine production in Cephalotaxu mannii suspension cells

目的研究L-色氨酸及其衍生物5-甲基-DL-色氨酸(5-MT)对海南粗榧悬浮细胞生长及三尖杉酯类碱合成的影响。方法在细胞培养第15天,向海南粗榧悬浮培养物中添加一定量的L-色氨酸或5-MT,测定细胞生长、产物量以及代谢途径中关键酶的活力。结果 L-色氨酸与5-MT都能促进三尖杉酯类碱的合成。添加5 mg/L 5-MT时,产物量最高(2.944 mg/L);添加10 mg/L L-色氨酸和5 mg/L 5-MT后,三尖杉酯类碱产量分别是对照(1.343 mg/L)的1.947、2.192倍;而悬浮细胞生物量分别比对照(2.406 g/L)降低了9.35%、18.04%。同时,3-脱氧-D-阿拉伯庚酮糖-7-磷酸合成酶活性分别比对照(0.67 U/mg)降低了12.4%、5.57%;苯丙氨酸解氨酶活性分别比对照(78.21 U/mg)增加了37.72%、28.02%;酚类物质积累比对照(0.36mg/mL)增加了19.14%、9.61%。结论 L-色氨酸及其衍生物5-MT能抑制代谢支路,促进代谢流向产物三尖杉酯类碱的方向。

Objective To investigate the effects of L-tryptophan and its derivative 5-methyl-DL-tryptophan （5-MT） on suspension cells growth and cephalotaxine production of Cephalotaxu mannii. Methods The cell suspension cultures were treated with L-tryptophan and 5-MT on day 15, respectively. Then the cell growth, cephalotaxine production, and activity of key enzymes in the metabolism pathway were determined. Results L-tryptophan and 5-MT could enhance cephalotaxine production. The cultures treated with 5 mg/L L-tryptophan showed the highest cephalotaxine yield （2.944 mg/L）. While treated with 10 mg/L L-tryptophan and 5 mg/L 5-MT, the cephalotaxine yields were 1.947 and 2.192 times of the control culture （1.343 mg/L）; The biomass of suspension cultures were decreased by 9.35% and 18.04%, respectively, less than those in the control group （2.406 g/L）; The activity of 3-deoxy-D-arabino- heptulosonate-7-phosphate synthase was decreased by 12.4% and 5.57% compared with the control （0.67 U/mg）; The activity of phenylalanine ammonium-lyase activity increased by 37.72% and 28.02% and the total phenolics content increased by 19.14% and 9.61% compared with the control （78.21 U/mg and 0.36 mg/mL）. Conclusion L-tryptophan and its derivative 5-MT can inhibit the L-tryptophan biosynthetic pathway and promote the accumulation of cephalotaxus alkaloids.